Commit 124969eb authored by Melanie Darcis's avatar Melanie Darcis
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updated latex documentation of models based on current doxygen model

documentation.



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@9196 2fb0f335-1f38-0410-981e-8018bf24f1b0
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\-This model implements a one-\/phase flow of a compressible fluid, that consists of two components, using a standard \-Darcy approach as the equation for the conservation of momentum\-: \[ v_{D} = - \frac{\textbf K}{\mu} \left(\text{grad} p - \varrho {\textbf g} \right) \]
This model implements a one-\/phase flow of a compressible fluid, that consists of two components, using a standard Darcy approach as the equation for the conservation of momentum\-: \[ v_{D} = - \frac{\textbf K}{\mu} \left(\text{grad} p - \varrho {\textbf g} \right) \]
\-Gravity can be enabled or disabled via the property system. \-By inserting this into the continuity equation, one gets \[ \Phi \frac{\partial \varrho}{\partial t} - \text{div} \left\{ \varrho \frac{\textbf K}{\mu} \left(\text{grad}\, p - \varrho {\textbf g} \right) \right\} = q \;, \]
Gravity can be enabled or disabled via the property system. By inserting this into the continuity equation, one gets \[ \Phi \frac{\partial \varrho}{\partial t} - \text{div} \left\{ \varrho \frac{\textbf K}{\mu} \left(\text{grad}\, p - \varrho {\textbf g} \right) \right\} = q \;, \]
\-The transport of the components is described by the following equation\-: \[ \Phi \frac{ \partial \varrho x}{\partial t} - \text{div} \left( \varrho \frac{{\textbf K} x}{\mu} \left( \text{grad}\, p - \varrho {\textbf g} \right) + \varrho \tau \Phi D \text{grad} x \right) = q. \]
The transport of the components is described by the following equation\-: \[ \Phi \frac{ \partial \varrho x}{\partial t} - \text{div} \left( \varrho \frac{{\textbf K} x}{\mu} \left( \text{grad}\, p - \varrho {\textbf g} \right) + \varrho \tau \Phi D \text{grad} x \right) = q. \]
\-All equations are discretized using a fully-\/coupled vertex-\/centered finite volume (box) scheme as spatial and the implicit \-Euler method as time discretization.
All equations are discretized using a fully-\/coupled vertex-\/centered finite volume (box) scheme as spatial and the implicit Euler method as time discretization.
\-The primary variables are the pressure $p$ and the mole or mass fraction of dissolved component $x$.
The primary variables are the pressure $p$ and the mole or mass fraction of dissolved component $x$.
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\-Single-\/phase, isothermal flow model, which solves the mass continuity equation \[ \phi \frac{\partial \varrho}{\partial t} + \text{div} (- \varrho \frac{\textbf K}{\mu} ( \textbf{grad}\, p -\varrho {\textbf g})) = q, \] discretized using a vertex-\/centered finite volume (box) scheme as spatial and the implicit \-Euler method as time discretization. \-The model supports compressible as well as incompressible fluids.
Single-\/phase, isothermal flow model, which solves the mass continuity equation \[ \phi \frac{\partial \varrho}{\partial t} + \text{div} (- \varrho \frac{\textbf K}{\mu} ( \textbf{grad}\, p -\varrho {\textbf g})) = q, \] discretized using a vertex-\/centered finite volume (box) scheme as spatial and the implicit Euler method as time discretization. The model supports compressible as well as incompressible fluids.
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\-This model solves equations of the form \[ \textbf{div}\, \boldsymbol v = q. \] \-The velocity $ \boldsymbol v $ is the single phase \-Darcy velocity\-: \[ \boldsymbol v = -\frac{1}{\mu} \boldsymbol K \left(\textbf{grad}\, p + \rho \, g \, \textbf{grad}\, z\right), \] where $ p $ is the pressure, $ \boldsymbol K $ the absolute permeability, $ \mu $ the viscosity, $ \rho $ the density, and $ g $ the gravity constant, and $ q $ is the source term. \-At the boundary, $ p = p_D $ on $ \Gamma_{Dirichlet} $, and $ \boldsymbol v \cdot \boldsymbol n = q_N$ on $ \Gamma_{Neumann} $.
This model solves equations of the form \[ \textbf{div}\, \boldsymbol v = q. \] The velocity $ \boldsymbol v $ is the single phase Darcy velocity\-: \[ \boldsymbol v = -\frac{1}{\mu} \boldsymbol K \left(\textbf{grad}\, p + \rho \, g \, \textbf{grad}\, z\right), \] where $ p $ is the pressure, $ \boldsymbol K $ the absolute permeability, $ \mu $ the viscosity, $ \rho $ the density, and $ g $ the gravity constant, and $ q $ is the source term. At the boundary, $ p = p_D $ on $ \Gamma_{Dirichlet} $, and $ \boldsymbol v \cdot \boldsymbol n = q_N$ on $ \Gamma_{Neumann} $.
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\-This model implements two-\/phase two-\/component flow of two compressible and partially miscible fluids $\alpha \in \{ w, n \}$ composed of the two components $\kappa \in \{ w, a \}$. \-The standard multiphase \-Darcy approach is used as the equation for the conservation of momentum\-: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \]
This model implements two-\/phase two-\/component flow of two compressible and partially miscible fluids $\alpha \in \{ w, n \}$ composed of the two components $\kappa \in \{ w, a \}$. The standard multiphase Darcy approach is used as the equation for the conservation of momentum\-: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \]
\-By inserting this into the equations for the conservation of the components, one gets one transport equation for each component \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_\alpha X_\alpha^\kappa S_\alpha )} {\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha X_\alpha^\kappa \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} (\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g}) \right\} \nonumber \\ \nonumber \\ &-& \sum_\alpha \text{div} \left\{{\bf D}_{\alpha, pm}^\kappa \varrho_{\alpha} \text{grad}\, X^\kappa_{\alpha} \right\} - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{w, a\} \, , \alpha \in \{w, g\} \end{eqnarray*}
By inserting this into the equations for the conservation of the components, one gets one transport equation for each component \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_\alpha X_\alpha^\kappa S_\alpha )} {\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha X_\alpha^\kappa \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} (\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g}) \right\} \nonumber \\ \nonumber \\ &-& \sum_\alpha \text{div} \left\{{\bf D}_{\alpha, pm}^\kappa \varrho_{\alpha} \text{grad}\, X^\kappa_{\alpha} \right\} - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{w, a\} \, , \alpha \in \{w, g\} \end{eqnarray*}
\-This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit \-Euler method as temporal discretization.
This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit Euler method as temporal discretization.
\-By using constitutive relations for the capillary pressure $p_c = p_n - p_w$ and relative permeability $k_{r\alpha}$ and taking advantage of the fact that $S_w + S_n = 1$ and $X^\kappa_w + X^\kappa_n = 1$, the number of unknowns can be reduced to two. \-The used primary variables are, like in the two-\/phase model, either $p_w$ and $S_n$ or $p_n$ and $S_w$. \-The formulation which ought to be used can be specified by setting the {\ttfamily \-Formulation} property to either \-Two\-P\-Two\-C\-Indices\-::p\-Ws\-N or \-Two\-P\-Two\-C\-Indices\-::p\-Ns\-W. \-By default, the model uses $p_w$ and $S_n$. \-Moreover, the second primary variable depends on the phase state, since a primary variable switch is included. \-The phase state is stored for all nodes of the system. \-Following cases can be distinguished\-:
By using constitutive relations for the capillary pressure $p_c = p_n - p_w$ and relative permeability $k_{r\alpha}$ and taking advantage of the fact that $S_w + S_n = 1$ and $X^\kappa_w + X^\kappa_n = 1$, the number of unknowns can be reduced to two. The used primary variables are, like in the two-\/phase model, either $p_w$ and $S_n$ or $p_n$ and $S_w$. The formulation which ought to be used can be specified by setting the {\ttfamily Formulation} property to either Two\-P\-Two\-C\-Indices\-::p\-Ws\-N or Two\-P\-Two\-C\-Indices\-::p\-Ns\-W. By default, the model uses $p_w$ and $S_n$. Moreover, the second primary variable depends on the phase state, since a primary variable switch is included. The phase state is stored for all nodes of the system. Following cases can be distinguished\-:
\begin{itemize}
\item \-Both phases are present\-: \-The saturation is used (either $S_n$ or $S_w$, dependent on the chosen {\ttfamily \-Formulation}), as long as $ 0 < S_\alpha < 1$.
\item \-Only wetting phase is present\-: \-The mass fraction of, e.\-g., air in the wetting phase $X^a_w$ is used, as long as the maximum mass fraction is not exceeded $(X^a_w<X^a_{w,max})$
\item \-Only non-\/wetting phase is present\-: \-The mass fraction of, e.\-g., water in the non-\/wetting phase, $X^w_n$, is used, as long as the maximum mass fraction is not exceeded $(X^w_n<X^w_{n,max})$
\item Both phases are present\-: The saturation is used (either $S_n$ or $S_w$, dependent on the chosen {\ttfamily Formulation}), as long as $ 0 < S_\alpha < 1$.
\item Only wetting phase is present\-: The mass fraction of, e.\-g., air in the wetting phase $X^a_w$ is used, as long as the maximum mass fraction is not exceeded $(X^a_w<X^a_{w,max})$
\item Only non-\/wetting phase is present\-: The mass fraction of, e.\-g., water in the non-\/wetting phase, $X^w_n$, is used, as long as the maximum mass fraction is not exceeded $(X^w_n<X^w_{n,max})$
\end{itemize}
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Provides a Finite Volume implementation for the pressure equation of a compressible system with two components. An I\-M\-P\-E\-S-\/like method is used for the sequential solution of the problem. Diffusion is neglected, capillarity can be regarded. Isothermal conditions and local thermodynamic equilibrium are assumed. Gravity is included. \[ c_{total}\frac{\partial p}{\partial t} + \sum_{\kappa} \frac{\partial v_{total}}{\partial C^{\kappa}} \nabla \cdot \left( \sum_{\alpha} X^{\kappa}_{\alpha} \varrho_{\alpha} \bf{v}_{\alpha}\right) = \sum_{\kappa} \frac{\partial v_{total}}{\partial C^{\kappa}} q^{\kappa}, \] where $\bf{v}_{\alpha} = - \lambda_{\alpha} \bf{K} \left(\nabla p_{\alpha} + \rho_{\alpha} \bf{g} \right) $. $ c_{total} $ represents the total compressibility, for constant porosity this yields $ - \frac{\partial V_{total}}{\partial p_{\alpha}} $, $p_{\alpha} $ denotes the phase pressure, $ \bf{K} $ the absolute permeability, $ \lambda_{\alpha} $ the phase mobility, $ \rho_{\alpha} $ the phase density and $ \bf{g} $ the gravity constant and $ C^{\kappa} $ the total \hyperlink{a00070}{Component} concentration. See paper S\-P\-E 99619 or \char`\"{}\-Analysis of a Compositional Model for Fluid
Flow in Porous Media\char`\"{} by Chen, Qin and Ewing for derivation.
The pressure base class \hyperlink{a00131}{F\-V\-Pressure} assembles the matrix and right-\/hand-\/side vector and solves for the pressure vector, whereas this class provides the actual entries for the matrix and R\-H\-S vector. The partial derivatives of the actual fluid volume $ v_{total} $ are gained by using a secant method.
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The transport step is described by the finite volume model for the solution of the transport equation for compositional two-\/phase flow. \[ \frac{\partial C^\kappa}{\partial t} = - \nabla \cdot \left( \sum_{\alpha} X^{\kappa}_{\alpha} \varrho_{alpha} \bf{v}_{\alpha}\right) + q^{\kappa}, \] where $ \bf{v}_{\alpha} = - \lambda_{\alpha} \bf{K} \left(\nabla p_{\alpha} + \rho_{\alpha} \bf{g} \right) $. $ p_{\alpha} $ denotes the phase pressure, $ \bf{K} $ the absolute permeability, $ \lambda_{\alpha} $ the phase mobility, $ \rho_{\alpha} $ the phase density and $ \bf{g} $ the gravity constant and $ C^{\kappa} $ the total \hyperlink{a00070}{Component} concentration. The whole flux contribution for each cell is subdivided into a storage term, a flux term and a source term. Corresponding functions ({\ttfamily \hyperlink{a00145_a13998fc22be58456c4bf8e3f4b12d89c}{get\-Flux()}} and {\ttfamily \hyperlink{a00145_a40fc97d83d3d15cdd29574d3a38fdafb}{get\-Flux\-On\-Boundary()}}) are provided, internal sources are directly treated.
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\-This model implements a non-\/isothermal two-\/phase flow of two compressible and partly miscible fluids $\alpha \in \{ w, n \}$. \-Thus each component $\kappa \{ w, a \}$ can be present in each phase. \-Using the standard multiphase \-Darcy approach a mass balance equation is solved\-: \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_\alpha X_\alpha^\kappa S_\alpha )}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha X_\alpha^\kappa \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} (\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g}) \right\}\\ &-& \sum_\alpha \text{div} \left\{{\bf D}_{\alpha, pm}^\kappa \varrho_{\alpha} \text{grad}\, X^\kappa_{\alpha} \right\} - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{w, a\} \, , \alpha \in \{w, n\} \end{eqnarray*} \-For the energy balance, local thermal equilibrium is assumed which results in one energy conservation equation for the porous solid matrix and the fluids\-: \begin{eqnarray*} && \phi \frac{\partial \left( \sum_\alpha \varrho_\alpha u_\alpha S_\alpha \right)}{\partial t} + \left( 1 - \phi \right) \frac{\partial (\varrho_s c_s T)}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha h_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left( \text{grad}\, p_\alpha - \varrho_\alpha \mathbf{g} \right) \right\} \\ &-& \text{div} \left( \lambda_{pm} \text{grad} \, T \right) - q^h = 0 \qquad \alpha \in \{w, n\} \end{eqnarray*}
This model implements a non-\/isothermal two-\/phase flow of two compressible and partly miscible fluids $\alpha \in \{ w, n \}$. Thus each component $\kappa \{ w, a \}$ can be present in each phase. Using the standard multiphase Darcy approach a mass balance equation is solved\-: \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_\alpha X_\alpha^\kappa S_\alpha )}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha X_\alpha^\kappa \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} (\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g}) \right\}\\ &-& \sum_\alpha \text{div} \left\{{\bf D}_{\alpha, pm}^\kappa \varrho_{\alpha} \text{grad}\, X^\kappa_{\alpha} \right\} - \sum_\alpha q_\alpha^\kappa = 0 \qquad \kappa \in \{w, a\} \, , \alpha \in \{w, n\} \end{eqnarray*} For the energy balance, local thermal equilibrium is assumed which results in one energy conservation equation for the porous solid matrix and the fluids\-: \begin{eqnarray*} && \phi \frac{\partial \left( \sum_\alpha \varrho_\alpha u_\alpha S_\alpha \right)}{\partial t} + \left( 1 - \phi \right) \frac{\partial (\varrho_s c_s T)}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha h_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left( \text{grad}\, p_\alpha - \varrho_\alpha \mathbf{g} \right) \right\} \\ &-& \text{div} \left( \lambda_{pm} \text{grad} \, T \right) - q^h = 0 \qquad \alpha \in \{w, n\} \end{eqnarray*}
\-This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit \-Euler method as temporal discretization.
This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit Euler method as temporal discretization.
\-By using constitutive relations for the capillary pressure $p_c = p_n - p_w$ and relative permeability $k_{r\alpha}$ and taking advantage of the fact that $S_w + S_n = 1$ and $X^\kappa_w + X^\kappa_n = 1$, the number of unknowns can be reduced to two. \-If both phases are present the primary variables are, like in the nonisothermal two-\/phase model, either $p_w$, $S_n$ and temperature or $p_n$, $S_w$ and temperature. \-The formulation which ought to be used can be specified by setting the {\ttfamily \-Formulation} property to either {\ttfamily \-Two\-P\-Two\-C\-Indices\-::p\-Ws\-N} or {\ttfamily \-Two\-P\-Two\-C\-Indices\-::p\-Ns\-W}. \-By default, the model uses $p_w$ and $S_n$. \-In case that only one phase (nonwetting or wetting phase) is present the second primary variable represents a mass fraction. \-The correct assignment of the second primary variable is performed by a phase state dependent primary variable switch. \-The phase state is stored for all nodes of the system. \-The following cases can be distinguished\-:
By using constitutive relations for the capillary pressure $p_c = p_n - p_w$ and relative permeability $k_{r\alpha}$ and taking advantage of the fact that $S_w + S_n = 1$ and $X^\kappa_w + X^\kappa_n = 1$, the number of unknowns can be reduced to two. If both phases are present the primary variables are, like in the nonisothermal two-\/phase model, either $p_w$, $S_n$ and temperature or $p_n$, $S_w$ and temperature. The formulation which ought to be used can be specified by setting the {\ttfamily Formulation} property to either {\ttfamily Two\-P\-Two\-C\-Indices\-::p\-Ws\-N} or {\ttfamily Two\-P\-Two\-C\-Indices\-::p\-Ns\-W}. By default, the model uses $p_w$ and $S_n$. In case that only one phase (nonwetting or wetting phase) is present the second primary variable represents a mass fraction. The correct assignment of the second primary variable is performed by a phase state dependent primary variable switch. The phase state is stored for all nodes of the system. The following cases can be distinguished\-:
\begin{itemize}
\item \-Both phases are present\-: \-The saturation is used (either $S_n$ or $S_w$, dependent on the chosen formulation).
\item \-Only wetting phase is present\-: \-The mass fraction of air in the wetting phase $X^a_w$ is used.
\item \-Only non-\/wetting phase is present\-: \-The mass fraction of water in the non-\/wetting phase, $X^w_n$, is used.
\item Both phases are present\-: The saturation is used (either $S_n$ or $S_w$, dependent on the chosen formulation).
\item Only wetting phase is present\-: The mass fraction of air in the wetting phase $X^a_w$ is used.
\item Only non-\/wetting phase is present\-: The mass fraction of water in the non-\/wetting phase, $X^w_n$, is used.
\end{itemize}
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\-This model implements two-\/phase flow of two immiscible fluids $\alpha \in \{ w, n \}$ using a standard multiphase \-Darcy approach as the equation for the conservation of momentum, i.\-e. \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \textbf{K} \left(\textbf{grad}\, p_\alpha - \varrho_{\alpha} {\textbf g} \right) \]
This model implements two-\/phase flow of two immiscible fluids $\alpha \in \{ w, n \}$ using a standard multiphase Darcy approach as the equation for the conservation of momentum, i.\-e. \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \textbf{K} \left(\textbf{grad}\, p_\alpha - \varrho_{\alpha} {\textbf g} \right) \]
\-By inserting this into the equation for the conservation of the phase mass, one gets \[ \phi \frac{\partial \varrho_\alpha S_\alpha}{\partial t} - \text{div} \left\{ \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\textbf{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \right\} - q_\alpha = 0 \;, \]
By inserting this into the equation for the conservation of the phase mass, one gets \[ \phi \frac{\partial \varrho_\alpha S_\alpha}{\partial t} - \text{div} \left\{ \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\textbf{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \right\} - q_\alpha = 0 \;, \]
\-These equations are discretized by a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit \-Euler method as time discretization.
These equations are discretized by a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit Euler method as time discretization.
\-By using constitutive relations for the capillary pressure $p_c = p_n - p_w$ and relative permeability $k_{r\alpha}$ and taking advantage of the fact that $S_w + S_n = 1$, the number of unknowns can be reduced to two. \-Currently the model supports choosing either $p_w$ and $S_n$ or $p_n$ and $S_w$ as primary variables. \-The formulation which ought to be used can be specified by setting the {\ttfamily \-Formulation} property to either {\ttfamily \-Two\-P\-Common\-Indices\-::p\-Ws\-N} or {\ttfamily \-Two\-P\-Common\-Indices\-::p\-Ns\-W}. \-By default, the model uses $p_w$ and $S_n$.
By using constitutive relations for the capillary pressure $p_c = p_n - p_w$ and relative permeability $k_{r\alpha}$ and taking advantage of the fact that $S_w + S_n = 1$, the number of unknowns can be reduced to two. Currently the model supports choosing either $p_w$ and $S_n$ or $p_n$ and $S_w$ as primary variables. The formulation which ought to be used can be specified by setting the {\ttfamily Formulation} property to either {\ttfamily Two\-P\-Common\-Indices\-::p\-Ws\-N} or {\ttfamily Two\-P\-Common\-Indices\-::p\-Ns\-W}. By default, the model uses $p_w$ and $S_n$.
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This model solves equations of the form \[ \phi \left( \rho_w \frac{\partial S_w}{\partial t} + \rho_n \frac{\partial S_n}{\partial t}\right) + \textbf{div}\, \boldsymbol{v}_{total} = q. \] The definition of the total velocity $\boldsymbol{v}_{total}$ depends on the choice of the primary pressure variable. Further, fluids can be assumed to be compressible or incompressible which is toggled by the Property {\ttfamily Enable\-Compressibility}). In the incompressible case a wetting $(w) $ phase pressure as primary variable leads to
This model solves equations of the form \[ \phi \left( \rho_w \frac{\partial S_w}{\partial t} + \rho_n \frac{\partial S_n}{\partial t}\right) + \textbf{div}\, \boldsymbol{v}_{total} = q. \] The definition of the total velocity $\boldsymbol{v}_{total}$ depends on the choice of the primary pressure variable. Further, fluids can be assumed to be compressible or incompressible (Property\-: {\ttfamily Enable\-Compressibility}). In the incompressible case a wetting $(w) $ phase pressure as primary variable leads to
\[ - \textbf{div}\, \left[\lambda \boldsymbol K \left(\textbf{grad}\, p_w + f_n \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \]
a non-\/wetting ( $ n $) phase pressure yields \[ - \textbf{div}\, \left[\lambda \boldsymbol K \left(\textbf{grad}\, p_n - f_w \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \] and a global pressure leads to \[ - \textbf{div}\, \left[\lambda \boldsymbol K \left(\textbf{grad}\, p_{global} + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q. \] \-Here, $ p_\alpha $ is a phase pressure, $ p_ {global} $ the global pressure of a classical fractional flow formulation (see e.\-g. \-P. \-Binning and \-M. \-A. \-Celia, ''\-Practical implementation of the fractional flow approach to multi-\/phase flow simulation'', \-Advances in water resources, vol. 22, no. 5, pp. 461-\/478, 1999.), $ p_c = p_n - p_w $ is the capillary pressure, $ \boldsymbol K $ the absolute permeability, $ \lambda = \lambda_w + \lambda_n $ the total mobility depending on the saturation ( $ \lambda_\alpha = k_{r_\alpha} / \mu_\alpha $), $ f_\alpha = \lambda_\alpha / \lambda $ the
fractional flow function of a phase, $ \rho_\alpha $ a phase density, $ g $ the gravity constant and $ q $ the source term.
a non-\/wetting ( $ n $) phase pressure yields \[ - \textbf{div}\, \left[\lambda \boldsymbol K \left(\textbf{grad}\, p_n - f_w \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \] and a global pressure leads to \[ - \textbf{div}\, \left[\lambda \boldsymbol K \left(\textbf{grad}\, p_{global} + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q. \] Here, $ p_\alpha $ is a phase pressure, $ p_ {global} $ the global pressure of a classical fractional flow formulation (see e.\-g. P. Binning and M. A. Celia, ''Practical implementation of the fractional flow approach to multi-\/phase flow simulation'', Advances in water resources, vol. 22, no. 5, pp. 461-\/478, 1999.), $ p_c = p_n - p_w $ is the capillary pressure, $ \boldsymbol K $ the absolute permeability, $ \lambda = \lambda_w + \lambda_n $ the total mobility depending on the saturation ( $ \lambda_\alpha = k_{r_\alpha} / \mu_\alpha $), $ f_\alpha = \lambda_\alpha / \lambda $ the fractional flow function of a phase, $ \rho_\alpha $ a phase density, $ g $ the gravity constant and $ q $ the source term.
\-For all cases, $ p = p_D $ on $ \Gamma_{Dirichlet} $, and $ \boldsymbol v_{total} \cdot \boldsymbol n = q_N $ on $ \Gamma_{Neumann} $.
\-The slightly compressible case is only implemented for phase pressures! \-In this case for a wetting $(w) $ phase pressure as primary variable the equations are formulated as \[ \phi \left( \rho_w \frac{\partial S_w}{\partial t} + \rho_n \frac{\partial S_n}{\partial t}\right) - \textbf{div}\, \left[\lambda \boldsymbol{K} \left(\textbf{grad}\, p_w + f_n \, \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \] and for a non-\/wetting ( $ n $) phase pressure as \[ \phi \left( \rho_w \frac{\partial S_w}{\partial t} + \rho_n \frac{\partial S_n}{\partial t}\right) - \textbf{div}\, \left[\lambda \boldsymbol{K} \left(\textbf{grad}\, p_n - f_w \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \] \-In this slightly compressible case the following definitions are valid\-: $ \lambda = \rho_w \lambda_w + \rho_n \lambda_n $, $ f_\alpha = (\rho_\alpha \lambda_\alpha) / \lambda $ \-This model assumes that temporal changes in density are
very small and thus terms of temporal derivatives are negligible in the pressure equation. \-Depending on the formulation the terms including time derivatives of saturations are simplified by inserting $ S_w + S_n = 1 $.
\-In the \-I\-M\-P\-E\-S models the default setting is\-:
\begin{itemize}
\item formulation\-: $ p_w-S_w $ (\-Property\-: {\ttfamily \-Formulation} defined as {\ttfamily \hyperlink{a00056_a04294fbcf0af5328016a160dbd8bfff9}{\-Decoupled\-Two\-P\-Common\-Indices\-::pw\-Sw}})
\item compressibility\-: disabled (\-Property\-: {\ttfamily \-Enable\-Compressibility} set to {\ttfamily false})
\end{itemize}
For all cases, $ p = p_D $ on $ \Gamma_{Dirichlet} $, and $ \boldsymbol v_{total} \cdot \boldsymbol n = q_N $ on $ \Gamma_{Neumann} $.
The slightly compressible case is only implemented for phase pressures! In this case for a wetting $(w) $ phase pressure as primary variable the equations are formulated as \[ \phi \left( \rho_w \frac{\partial S_w}{\partial t} + \rho_n \frac{\partial S_n}{\partial t}\right) - \textbf{div}\, \left[\lambda \boldsymbol{K} \left(\textbf{grad}\, p_w + f_n \, \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \] and for a non-\/wetting ( $ n $) phase pressure as \[ \phi \left( \rho_w \frac{\partial S_w}{\partial t} + \rho_n \frac{\partial S_n}{\partial t}\right) - \textbf{div}\, \left[\lambda \boldsymbol{K} \left(\textbf{grad}\, p_n - f_w \textbf{grad}\, p_c + \sum f_\alpha \rho_\alpha \, g \, \textbf{grad}\, z\right)\right] = q, \] In this slightly compressible case the following definitions are valid\-: $ \lambda = \rho_w \lambda_w + \rho_n \lambda_n $, $ f_\alpha = (\rho_\alpha \lambda_\alpha) / \lambda $ This model assumes that temporal changes in density are very small and thus terms of temporal derivatives are negligible in the pressure equation. Depending on the formulation the terms including time derivatives of saturations are simplified by inserting $ S_w + S_n = 1 $.
......@@ -4,22 +4,13 @@
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\-This model solves equations of the form
This model solves equations of the form
\[ \phi \frac{\partial (\rho_\alpha S_\alpha)}{\partial t} + \textbf{div}\, (\rho_\alpha \boldsymbol{v_\alpha}) = q_\alpha, \]
where $ S_\alpha $ is the saturation of phase $ \alpha $ (wetting $(w) $, non-\/wetting $(n) $) and $ \boldsymbol v_\alpha $ is the phase velocity defined by the multi-\/phase \-Darcy equation. \-If a phase velocity is reconstructed from the pressure solution it can be directly inserted into the previous equation. \-In the incompressible case the equation is further divided by the phase density $ \rho_\alpha $. \-If a total velocity is reconstructed the saturation equation is reformulated into\-:
where $ S_\alpha $ is the saturation of phase $ \alpha $ (wetting $(w) $, non-\/wetting $(n) $) and $ \boldsymbol v_\alpha $ is the phase velocity defined by the multi-\/phase Darcy equation. If a phase velocity is reconstructed from the pressure solution it can be directly inserted into the previous equation. In the incompressible case the equation is further divided by the phase density $ \rho_\alpha $. If a total velocity is reconstructed the saturation equation is reformulated into\-:
\[ \phi \frac{\partial S_w}{\partial t} + f_w \textbf{div}\, \boldsymbol{v}_{t} + f_w \lambda_n \boldsymbol{K}\left(\textbf{grad}\, p_c + (\rho_n-\rho_w) \, g \, \textbf{grad} z \right)= q_\alpha, \] to get a wetting phase saturation or \[ \phi \frac{\partial S_n}{\partial t} + f_n \textbf{div}\, \boldsymbol{v}_{t} - f_n \lambda_w \boldsymbol{K}\left(\textbf{grad}\, p_c + (\rho_n-\rho_w) \, g \, \textbf{grad} z \right)= q_\alpha, \] if the non-\/wetting phase saturation is the primary transport variable.
\-The total velocity formulation is only implemented for incompressible fluids and $ f_\alpha $ is the fractional flow function, $ \lambda_\alpha $ is the mobility, $ \boldsymbol K $ the absolute permeability, $ p_c $ the capillary pressure, $ \rho $ the fluid density, $ g $ the gravity constant, and $ q $ the source term.
\-In the \-I\-M\-P\-E\-S models the default setting is\-:
\begin{itemize}
\item formulation\-: $ p_w-S_w $ (\-Property\-: {\ttfamily \-Formulation} defined as {\ttfamily \hyperlink{a00056_a04294fbcf0af5328016a160dbd8bfff9}{\-Decoupled\-Two\-P\-Common\-Indices\-::pw\-Sw}})
\item compressibility\-: disabled (\-Property\-: {\ttfamily \-Enable\-Compressibility} set to {\ttfamily false})
\end{itemize}
The total velocity formulation is only implemented for incompressible fluids and $ f_\alpha $ is the fractional flow function, $ \lambda_\alpha $ is the mobility, $ \boldsymbol K $ the absolute permeability, $ p_c $ the capillary pressure, $ \rho $ the fluid density, $ g $ the gravity constant, and $ q $ the source term.
......@@ -4,13 +4,13 @@
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\-This model implements a non-\/isothermal two-\/phase flow for two immiscible fluids $\alpha \in \{ w, n \}$. \-Using the standard multiphase \-Darcy approach, the mass conservation equations for both phases can be described as follows\-: \[ \phi \frac{\partial \phi \varrho_\alpha S_\alpha}{\partial t} - \text{div} \left\{ \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathrm{K} \left( \textrm{grad}\, p_\alpha - \varrho_{\alpha} \mathbf{g} \right) \right\} - q_\alpha = 0 \qquad \alpha \in \{w, n\} \]
This model implements a non-\/isothermal two-\/phase flow for two immiscible fluids $\alpha \in \{ w, n \}$. Using the standard multiphase Darcy approach, the mass conservation equations for both phases can be described as follows\-: \[ \phi \frac{\partial \phi \varrho_\alpha S_\alpha}{\partial t} - \text{div} \left\{ \varrho_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathrm{K} \left( \textrm{grad}\, p_\alpha - \varrho_{\alpha} \mathbf{g} \right) \right\} - q_\alpha = 0 \qquad \alpha \in \{w, n\} \]
\-For the energy balance, local thermal equilibrium is assumed. \-This results in one energy conservation equation for the porous solid matrix and the fluids\-:
For the energy balance, local thermal equilibrium is assumed. This results in one energy conservation equation for the porous solid matrix and the fluids\-:
\begin{align*} \frac{\partial \phi \sum_\alpha \varrho_\alpha u_\alpha S_\alpha}{\partial t} & + \left( 1 - \phi \right) \frac{\partial (\varrho_s c_s T)}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha h_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left( \textbf{grad}\,p_\alpha - \varrho_\alpha \mbox{\bf g} \right) \right\} \\ & - \text{div} \left(\lambda_{pm} \textbf{grad} \, T \right) - q^h = 0, \qquad \alpha \in \{w, n\} \;, \end{align*} where $h_\alpha$ is the specific enthalpy of a fluid phase $\alpha$ and $u_\alpha = h_\alpha - p_\alpha/\varrho_\alpha$ is the specific internal energy of the phase.
\-The equations are discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit \-Euler method as time discretization.
The equations are discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit Euler method as time discretization.
\-Currently the model supports choosing either $p_w$, $S_n$ and $T$ or $p_n$, $S_w$ and $T$ as primary variables. \-The formulation which ought to be used can be specified by setting the {\ttfamily \-Formulation} property to either {\ttfamily \-Two\-P\-N\-I\-Indices\-::p\-Ws\-N} or {\ttfamily \-Two\-P\-Indices\-::p\-Ns\-W}. \-By default, the model uses $p_w$, $S_n$ and $T$.
Currently the model supports choosing either $p_w$, $S_n$ and $T$ or $p_n$, $S_w$ and $T$ as primary variables. The formulation which ought to be used can be specified by setting the {\ttfamily Formulation} property to either {\ttfamily Two\-P\-N\-I\-Indices\-::p\-Ws\-N} or {\ttfamily Two\-P\-Indices\-::p\-Ns\-W}. By default, the model uses $p_w$, $S_n$ and $T$.
......@@ -4,23 +4,23 @@
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This model implements three-phase three-component flow of three fluid phases $\alpha \in \{ \text{water}, \text{gas}, \text{NAPL} \}$ each composed of up to three components $\kappa \in \{ \text{water}, \text{air}, \text{contaminant} \}$. The standard multiphase Darcy approach is used as the equation for the conservation of momentum: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \]
This model implements three-\/phase three-\/component flow of three fluid phases $\alpha \in \{ water, gas, NAPL \}$ each composed of up to three components $\kappa \in \{ water, air, contaminant \}$. The standard multiphase Darcy approach is used as the equation for the conservation of momentum\-: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \]
\-By inserting this into the equations for the conservation of the components, one transport equation for each component is obtained as \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_{\text{mol}, \alpha} x_\alpha^\kappa S_\alpha )}{\partial t} - \sum\limits_\alpha \text{div} \left\{ \frac{k_{r\alpha}}{\mu_\alpha} \varrho_{\text{mol}, \alpha} x_\alpha^\kappa \mbox{\bf K} (\text{grad}\, p_\alpha - \varrho_{\text{mass}, \alpha} \mbox{\bf g}) \right\} \nonumber \\ \nonumber \\ && - \sum\limits_\alpha \text{div} \left\{ D_{pm}^\kappa \varrho_{\text{mol}, \alpha } \text{grad}\, x_\alpha^\kappa \right\} - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha \end{eqnarray*}
By inserting this into the equations for the conservation of the components, one transport equation for each component is obtained as \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_{\text{mol}, \alpha} x_\alpha^\kappa S_\alpha )}{\partial t} - \sum\limits_\alpha \text{div} \left\{ \frac{k_{r\alpha}}{\mu_\alpha} \varrho_{\text{mol}, \alpha} x_\alpha^\kappa \mbox{\bf K} (\text{grad}\, p_\alpha - \varrho_{\text{mass}, \alpha} \mbox{\bf g}) \right\} \nonumber \\ \nonumber \\ && - \sum\limits_\alpha \text{div} \left\{ D_{pm}^\kappa \varrho_{\text{mol}, \alpha } \text{grad}\, x_\alpha^\kappa \right\} - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha \end{eqnarray*}
\-Note that these balance equations are molar.
Note that these balance equations are molar.
\-The equations are discretized using a fully-\/coupled vertex centered finite volume (\-B\-O\-X) scheme as spatial scheme and the implicit \-Euler method as temporal discretization.
The equations are discretized using a fully-\/coupled vertex centered finite volume (B\-O\-X) scheme as spatial scheme and the implicit Euler method as temporal discretization.
\-The model uses commonly applied auxiliary conditions like $S_w + S_n + S_g = 1$ for the saturations and $x^w_\alpha + x^a_\alpha + x^c_\alpha = 1$ for the mole fractions. \-Furthermore, the phase pressures are related to each other via capillary pressures between the fluid phases, which are functions of the saturation, e.\-g. according to the approach of \-Parker et al.
The model uses commonly applied auxiliary conditions like $S_w + S_n + S_g = 1$ for the saturations and $x^w_\alpha + x^a_\alpha + x^c_\alpha = 1$ for the mole fractions. Furthermore, the phase pressures are related to each other via capillary pressures between the fluid phases, which are functions of the saturation, e.\-g. according to the approach of Parker et al.
\-The used primary variables are dependent on the locally present fluid phases \-An adaptive primary variable switch is included. \-The phase state is stored for all nodes of the system. \-The following cases can be distinguished\-:
The used primary variables are dependent on the locally present fluid phases An adaptive primary variable switch is included. The phase state is stored for all nodes of the system. The following cases can be distinguished\-:
\begin{itemize}
\item \-All three phases are present\-: \-Primary variables are two saturations $(S_w$ and $S_n)$, and a pressure, in this case $p_g$.
\item \-Only the water phase is present\-: \-Primary variables are now the mole fractions of air and contaminant in the water phase $(x_w^a$ and $x_w^c)$, as well as the gas pressure, which is, of course, in a case where only the water phase is present, just the same as the water pressure.
\item \-Gas and \-N\-A\-P\-L phases are present\-: \-Primary variables $(S_n$, $x_g^w$, $p_g)$.
\item \-Water and \-N\-A\-P\-L phases are present\-: \-Primary variables $(S_n$, $x_w^a$, $p_g)$.
\item \-Only gas phase is present\-: \-Primary variables $(x_g^w$, $x_g^c$, $p_g)$.
\item \-Water and gas phases are present\-: \-Primary variables $(S_w$, $x_w^g$, $p_g)$.
\item All three phases are present\-: Primary variables are two saturations $(S_w$ and $S_n)$, and a pressure, in this case $p_g$.
\item Only the water phase is present\-: Primary variables are now the mole fractions of air and contaminant in the water phase $(x_w^a$ and $x_w^c)$, as well as the gas pressure, which is, of course, in a case where only the water phase is present, just the same as the water pressure.
\item Gas and N\-A\-P\-L phases are present\-: Primary variables $(S_n$, $x_g^w$, $p_g)$.
\item Water and N\-A\-P\-L phases are present\-: Primary variables $(S_n$, $x_w^a$, $p_g)$.
\item Only gas phase is present\-: Primary variables $(x_g^w$, $x_g^c$, $p_g)$.
\item Water and gas phases are present\-: Primary variables $(S_w$, $x_w^g$, $p_g)$.
\end{itemize}
......@@ -4,23 +4,23 @@
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This model implements three-phase three-component flow of three fluid phases $\alpha \in \{ \text{water}, \text{gas}, \text{NAPL} \}$ each composed of up to three components $\kappa \in \{ \text{water}, \text{air}, \text{contaminant} \}$. The standard multiphase Darcy approach is used as the equation for the conservation of momentum\-: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \]
This model implements three-\/phase three-\/component flow of three fluid phases $\alpha \in \{ water, gas, NAPL \}$ each composed of up to three components $\kappa \in \{ water, air, contaminant \}$. The standard multiphase Darcy approach is used as the equation for the conservation of momentum\-: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \mbox{\bf K} \left(\text{grad}\, p_\alpha - \varrho_{\alpha} \mbox{\bf g} \right) \]
\-By inserting this into the equations for the conservation of the components, one transport equation for each component is obtained as \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_{\text{mol}, \alpha} x_\alpha^\kappa S_\alpha )}{\partial t} - \sum\limits_\alpha \text{div} \left\{ \frac{k_{r\alpha}}{\mu_\alpha} \varrho_{\text{mol}, \alpha} x_\alpha^\kappa \mbox{\bf K} (\text{grad}\; p_\alpha - \varrho_{\text{mass}, \alpha} \mbox{\bf g}) \right\} \nonumber \\ \nonumber \\ && - \sum\limits_\alpha \text{div} \left\{ D_{pm}^\kappa \varrho_{\text{mol}, \alpha } \text{grad} \; x_\alpha^\kappa \right\} - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha \end{eqnarray*}
By inserting this into the equations for the conservation of the components, one transport equation for each component is obtained as \begin{eqnarray*} && \phi \frac{\partial (\sum_\alpha \varrho_{\text{mol}, \alpha} x_\alpha^\kappa S_\alpha )}{\partial t} - \sum\limits_\alpha \text{div} \left\{ \frac{k_{r\alpha}}{\mu_\alpha} \varrho_{\text{mol}, \alpha} x_\alpha^\kappa \mbox{\bf K} (\text{grad}\; p_\alpha - \varrho_{\text{mass}, \alpha} \mbox{\bf g}) \right\} \nonumber \\ \nonumber \\ && - \sum\limits_\alpha \text{div} \left\{ D_{pm}^\kappa \varrho_{\text{mol}, \alpha } \text{grad} \; x_\alpha^\kappa \right\} - q^\kappa = 0 \qquad \forall \kappa , \; \forall \alpha \end{eqnarray*}
\-Note that these balance equations above are molar. \-In addition to that, a single balance of thermal energy is formulated for the fluid-\/filled porous medium under the assumption of local thermal equilibrium \begin{eqnarray*} && \phi \frac{\partial \left( \sum_\alpha \varrho_\alpha u_\alpha S_\alpha \right)}{\partial t} + \left( 1 - \phi \right) \frac{\partial (\varrho_s c_s T)}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha h_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left( \text{grad}\, p_\alpha - \varrho_\alpha \mathbf{g} \right) \right\} \\ &-& \text{div} \left( \lambda_{pm} \text{grad} \, T \right) - q^h = 0 \qquad \alpha \in \{w, n, g\} \end{eqnarray*}
Note that these balance equations above are molar. In addition to that, a single balance of thermal energy is formulated for the fluid-\/filled porous medium under the assumption of local thermal equilibrium \begin{eqnarray*} && \phi \frac{\partial \left( \sum_\alpha \varrho_\alpha u_\alpha S_\alpha \right)}{\partial t} + \left( 1 - \phi \right) \frac{\partial (\varrho_s c_s T)}{\partial t} - \sum_\alpha \text{div} \left\{ \varrho_\alpha h_\alpha \frac{k_{r\alpha}}{\mu_\alpha} \mathbf{K} \left( \text{grad}\, p_\alpha - \varrho_\alpha \mathbf{g} \right) \right\} \\ &-& \text{div} \left( \lambda_{pm} \text{grad} \, T \right) - q^h = 0 \qquad \alpha \in \{w, n, g\} \end{eqnarray*}
\-The equations are discretized using a fully-\/coupled vertex centered finite volume (\-B\-O\-X) scheme as spatial scheme and the implicit \-Euler method as temporal discretization.
The equations are discretized using a fully-\/coupled vertex centered finite volume (B\-O\-X) scheme as spatial scheme and the implicit Euler method as temporal discretization.
\-The model uses commonly applied auxiliary conditions like $S_w + S_n + S_g = 1$ for the saturations and $x^w_\alpha + x^a_\alpha + x^c_\alpha = 1$ for the mole fractions. \-Furthermore, the phase pressures are related to each other via capillary pressures between the fluid phases, which are functions of the saturation, e.\-g. according to the approach of \-Parker et al.
The model uses commonly applied auxiliary conditions like $S_w + S_n + S_g = 1$ for the saturations and $x^w_\alpha + x^a_\alpha + x^c_\alpha = 1$ for the mole fractions. Furthermore, the phase pressures are related to each other via capillary pressures between the fluid phases, which are functions of the saturation, e.\-g. according to the approach of Parker et al.
\-The used primary variables are dependent on the locally present fluid phases \-An adaptive primary variable switch is included. \-The phase state is stored for all nodes of the system. \-The following cases can be distinguished\-:
The used primary variables are dependent on the locally present fluid phases An adaptive primary variable switch is included. The phase state is stored for all nodes of the system. The following cases can be distinguished\-:
\begin{itemize}
\item \-All three phases are present\-: \-Primary variables are two saturations $(S_w$ and $S_n)$, a pressure, in this case $p_g$, and the temperature $T$.
\item \-Only the water phase is present\-: \-Primary variables are now the mole fractions of air and contaminant in the water phase $(x_w^a$ and $x_w^c)$, as well as temperature and the gas pressure, which is, of course, in a case where only the water phase is present, just the same as the water pressure.
\item \-Gas and \-N\-A\-P\-L phases are present\-: \-Primary variables $(S_n$, $x_g^w$, $p_g$, $T)$.
\item \-Water and \-N\-A\-P\-L phases are present\-: \-Primary variables $(S_n$, $x_w^a$, $p_g$, $T)$.
\item \-Only gas phase is present\-: \-Primary variables $(x_g^w$, $x_g^c$, $p_g$, $T)$.
\item \-Water and gas phases are present\-: \-Primary variables $(S_w$, $x_w^g$, $p_g$, $T)$.
\item All three phases are present\-: Primary variables are two saturations $(S_w$ and $S_n)$, a pressure, in this case $p_g$, and the temperature $T$.
\item Only the water phase is present\-: Primary variables are now the mole fractions of air and contaminant in the water phase $(x_w^a$ and $x_w^c)$, as well as temperature and the gas pressure, which is, of course, in a case where only the water phase is present, just the same as the water pressure.
\item Gas and N\-A\-P\-L phases are present\-: Primary variables $(S_n$, $x_g^w$, $p_g$, $T)$.
\item Water and N\-A\-P\-L phases are present\-: Primary variables $(S_n$, $x_w^a$, $p_g$, $T)$.
\item Only gas phase is present\-: Primary variables $(x_g^w$, $x_g^c$, $p_g$, $T)$.
\item Water and gas phases are present\-: Primary variables $(S_w$, $x_w^g$, $p_g$, $T)$.
\end{itemize}
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\-This model implements a $M$-\/phase flow of a fluid mixture composed of $N$ chemical species. \-The phases are denoted by lower index $\alpha \in \{ 1, \dots, M \}$. \-All fluid phases are mixtures of $N \geq M - 1$ chemical species which are denoted by the upper index $\kappa \in \{ 1, \dots, N \} $.
This model implements a $M$-\/phase flow of a fluid mixture composed of $N$ chemical species. The phases are denoted by lower index $\alpha \in \{ 1, \dots, M \}$. All fluid phases are mixtures of $N \geq M - 1$ chemical species which are denoted by the upper index $\kappa \in \{ 1, \dots, N \} $.
\-The standard multi-\/phase \-Darcy law is used as the equation for the conservation of momentum\-: \[ v_\alpha = - \frac{k_{r\alpha}}{\mu_\alpha} \boldsymbol{K} \left( \text{grad}\left(p_\alpha - \varrho_{\alpha} g\right) \right) \]
The momentum approximation can either be selected via \char`\"{}\-Base\-Flux\-Variables\char`\"{}\-: Darcy (\hyperlink{a00026}{Box\-Darcy\-Flux\-Variables}) and Forchheimer (\hyperlink{a00029}{Box\-Forchheimer\-Flux\-Variables}) relations are available for all Box models.
\-By inserting this into the equations for the conservation of the mass of each component, one gets one mass-\/continuity equation for each component $\kappa$ \[ \sum_{\kappa} \left( \phi \frac{\partial \varrho_\alpha x_\alpha^\kappa S_\alpha}{\partial t} - \mathrm{div}\; \left\{ \frac{\varrho_\alpha}{\overline M_\alpha} x_\alpha^\kappa \frac{k_{r\alpha}}{\mu_\alpha} \boldsymbol{K} \text{grad}\left( p_\alpha - \varrho_{\alpha} g\right) \right\} \right) = q^\kappa \] with $\overline M_\alpha$ being the average molar mass of the phase $\alpha$\-: \[ \overline M_\alpha = \sum_\kappa M^\kappa \; x_\alpha^\kappa \]
By inserting this into the equations for the conservation of the mass of each component, one gets one mass-\/continuity equation for each component $\kappa$ \[ \sum_{\kappa} \left( \phi \frac{\partial \left(\varrho_\alpha x_\alpha^\kappa S_\alpha\right)}{\partial t} + \mathrm{div}\; \left\{ v_\alpha \frac{\varrho_\alpha}{\overline M_\alpha} x_\alpha^\kappa \right\} \right) = q^\kappa \] with $\overline M_\alpha$ being the average molar mass of the phase $\alpha$\-: \[ \overline M_\alpha = \sum_\kappa M^\kappa \; x_\alpha^\kappa \]
\-For the missing $M$ model assumptions, the model assumes that if a fluid phase is not present, the sum of the mole fractions of this fluid phase is smaller than $1$, i.\-e. \[ \forall \alpha: S_\alpha = 0 \implies \sum_\kappa x_\alpha^\kappa \leq 1 \]
For the missing $M$ model assumptions, the model assumes that if a fluid phase is not present, the sum of the mole fractions of this fluid phase is smaller than $1$, i.\-e. \[ \forall \alpha: S_\alpha = 0 \implies \sum_\kappa x_\alpha^\kappa \leq 1 \]
\-Also, if a fluid phase may be present at a given spatial location its saturation must be positive\-: \[ \forall \alpha: \sum_\kappa x_\alpha^\kappa = 1 \implies S_\alpha \geq 0 \]
Also, if a fluid phase may be present at a given spatial location its saturation must be positive\-: \[ \forall \alpha: \sum_\kappa x_\alpha^\kappa = 1 \implies S_\alpha \geq 0 \]
\-Since at any given spatial location, a phase is always either present or not present, one of the strict equalities on the right hand side is always true, i.\-e. \[ \forall \alpha: S_\alpha \left( \sum_\kappa x_\alpha^\kappa - 1 \right) = 0 \] always holds.
Since at any given spatial location, a phase is always either present or not present, one of the strict equalities on the right hand side is always true, i.\-e. \[ \forall \alpha: S_\alpha \left( \sum_\kappa x_\alpha^\kappa - 1 \right) = 0 \] always holds.
\-These three equations constitute a non-\/linear complementarity problem, which can be solved using so-\/called non-\/linear complementarity functions $\Phi(a, b)$ which have the property \[\Phi(a,b) = 0 \iff a \geq0 \land b \geq0 \land a \cdot b = 0 \]
These three equations constitute a non-\/linear complementarity problem, which can be solved using so-\/called non-\/linear complementarity functions $\Phi(a, b)$ which have the property \[\Phi(a,b) = 0 \iff a \geq0 \land b \geq0 \land a \cdot b = 0 \]
\-Several non-\/linear complementarity functions have been suggested, e.\-g. the \-Fischer-\/\-Burmeister function \[ \Phi(a,b) = a + b - \sqrt{a^2 + b^2} \;. \] \-This model uses \[ \Phi(a,b) = \min \{a, b \}\;, \] because of its piecewise linearity.
Several non-\/linear complementarity functions have been suggested, e.\-g. the Fischer-\/\-Burmeister function \[ \Phi(a,b) = a + b - \sqrt{a^2 + b^2} \;. \] This model uses \[ \Phi(a,b) = \min \{a, b \}\;, \] because of its piecewise linearity.
\-These equations are then discretized using a fully-\/implicit vertex centered finite volume scheme (often known as 'box'-\/scheme) for spatial discretization and the implicit \-Euler method as temporal discretization.
These equations are then discretized using a fully-\/implicit vertex centered finite volume scheme (often known as 'box'-\/scheme) for spatial discretization and the implicit Euler method as temporal discretization.
\-The model assumes local thermodynamic equilibrium and uses the following primary variables\-:
The model assumes local thermodynamic equilibrium and uses the following primary variables\-:
\begin{itemize}
\item \-The component fugacities $f^1, \dots, f^{N}$
\item \-The pressure of the first phase $p_1$
\item \-The saturations of the first $M-1$ phases $S_1, \dots, S_{M-1}$
\item \-Temperature $T$ if the energy equation is enabled
\item The component fugacities $f^1, \dots, f^{N}$
\item The pressure of the first phase $p_1$
\item The saturations of the first $M-1$ phases $S_1, \dots, S_{M-1}$
\item Temperature $T$ if the energy equation is enabled
\end{itemize}
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\-In the unsaturated zone, \-Richards' equation is frequently used to approximate the water distribution above the groundwater level. \-It can be derived from the two-\/phase equations, i.\-e. \[ \frac{\partial\;\phi S_\alpha \rho_\alpha}{\partial t} - \text{div} \left\{ \rho_\alpha \frac{k_{r\alpha}}{\mu_\alpha}\; \mathbf{K} \textbf{grad}\left[ p_\alpha - g\rho_\alpha \right] \right\} = q_\alpha, \] where $\alpha \in \{w, n\}$ is the fluid phase, $\rho_\alpha$ is the fluid density, $S_\alpha$ is the fluid saturation, $\phi$ is the porosity of the soil, $k_{r\alpha}$ is the relative permeability for the fluid, $\mu_\alpha$ is the fluid's dynamic viscosity, $\mathbf{K}$ is the intrinsic permeability, $p_\alpha$ is the fluid pressure and $g$ is the potential of the gravity field.
In the unsaturated zone, Richards' equation \[ \frac{\partial\;\phi S_w \rho_w}{\partial t} - \text{div} \left( \rho_w \frac{k_{rw}}{\mu_w} \; \mathbf{K} \; \text{\textbf{grad}}\left( p_w - g\rho_w \right) \right) = q_w, \] is frequently used to approximate the water distribution above the groundwater level.
\-In contrast to the full two-\/phase model, the \-Richards model assumes gas as the non-\/wetting fluid and that it exhibits a much lower viscosity than the (liquid) wetting phase. (\-For example at atmospheric pressure and at room temperature, the viscosity of air is only about $1\%$ of the viscosity of liquid water.) \-As a consequence, the $\frac{k_{r\alpha}}{\mu_\alpha}$ term typically is much larger for the gas phase than for the wetting phase. \-For this reason, the \-Richards model assumes that $\frac{k_{rn}}{\mu_n}$ is infinitly large. \-This implies that the pressure of the gas phase is equivalent to the static pressure distribution and that therefore, mass conservation only needs to be considered for the wetting phase.
It can be derived from the two-\/phase equations, i.\-e. \[ \frac{\partial\;\phi S_\alpha \rho_\alpha}{\partial t} - \text{div} \left( \rho_\alpha \frac{k_{r\alpha}}{\mu_\alpha}\; \mathbf{K} \; \text{\textbf{grad}}\left( p_\alpha - g\rho_\alpha \right) \right) = q_\alpha, \] where $\alpha \in \{w, n\}$ is the fluid phase, $\rho_\alpha$ is the fluid density, $S_\alpha$ is the fluid saturation, $\phi$ is the porosity of the soil, $k_{r\alpha}$ is the relative permeability for the fluid, $\mu_\alpha$ is the fluid's dynamic viscosity, $\mathbf{K}$ is the intrinsic permeability, $p_\alpha$ is the fluid pressure and $g$ is the potential of the gravity field.
\-The model thus choses the absolute pressure of the wetting phase $p_w$ as its only primary variable. \-The wetting phase saturation is calculated using the inverse of the capillary pressure, i.\-e. \[ S_w = p_c^{-1}(p_n - p_w) \] holds, where $p_n$ is a given reference pressure. \-Nota bene, that the last step is assumes that the capillary pressure-\/saturation curve can be uniquely inverted, so it is not possible to set the capillary pressure to zero when using the \-Richards model!
In contrast to the full two-\/phase model, the Richards model assumes gas as the non-\/wetting fluid and that it exhibits a much lower viscosity than the (liquid) wetting phase. (For example at atmospheric pressure and at room temperature, the viscosity of air is only about $1\%$ of the viscosity of liquid water.) As a consequence, the $\frac{k_{r\alpha}}{\mu_\alpha}$ term typically is much larger for the gas phase than for the wetting phase. For this reason, the Richards model assumes that $\frac{k_{rn}}{\mu_n}$ is infinitly large. This implies that the pressure of the gas phase is equivalent to the static pressure distribution and that therefore, mass conservation only needs to be considered for the wetting phase.
The model thus choses the absolute pressure of the wetting phase $p_w$ as its only primary variable. The wetting phase saturation is calculated using the inverse of the capillary pressure, i.\-e. \[ S_w = p_c^{-1}(p_n - p_w) \] holds, where $p_n$ is a given reference pressure. Nota bene, that the last step is assumes that the capillary pressure-\/saturation curve can be uniquely inverted, so it is not possible to set the capillary pressure to zero when using the Richards model!
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\-This model implements an isothermal two-\/component \-Stokes flow of a fluid solving a momentum balance, a mass balance and a conservation equation for one component.
This model implements an isothermal two-\/component Stokes flow of a fluid solving a momentum balance, a mass balance and a conservation equation for one component.
\-Momentum \-Balance\-: \[ \frac{\partial \left(\varrho_g {\boldsymbol{v}}_g\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left(p_g {\bf {I}} - \mu_g \left(\boldsymbol{\nabla} \boldsymbol{v}_g + \boldsymbol{\nabla} \boldsymbol{v}_g^T\right)\right) - \varrho_g {\bf g} = 0, \]
Momentum Balance\-: \[ \frac{\partial \left(\varrho_g {\boldsymbol{v}}_g\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left(p_g {\bf {I}} - \mu_g \left(\boldsymbol{\nabla} \boldsymbol{v}_g + \boldsymbol{\nabla} \boldsymbol{v}_g^T\right)\right) - \varrho_g {\bf g} = 0, \]
\-Mass balance equation\-: \[ \frac{\partial \varrho_g}{\partial t} + \boldsymbol{\nabla}\boldsymbol{\cdot}\left(\varrho_g {\boldsymbol{v}}_g\right) - q_g = 0 \]
Mass balance equation\-: \[ \frac{\partial \varrho_g}{\partial t} + \boldsymbol{\nabla}\boldsymbol{\cdot}\left(\varrho_g {\boldsymbol{v}}_g\right) - q_g = 0 \]
\hyperlink{a00047}{\-Component} mass balance equation\-: \[ \frac{\partial \left(\varrho_g X_g^\kappa\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left( \varrho_g {\boldsymbol{v}}_g X_g^\kappa - D^\kappa_g \varrho_g \boldsymbol{\nabla} X_g^\kappa \right) - q_g^\kappa = 0 \]
\hyperlink{a00070}{Component} mass balance equation\-: \[ \frac{\partial \left(\varrho_g X_g^\kappa\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left( \varrho_g {\boldsymbol{v}}_g X_g^\kappa - D^\kappa_g \varrho_g \boldsymbol{\nabla} X_g^\kappa \right) - q_g^\kappa = 0 \]
\-This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit \-Euler method as temporal discretization.
This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit Euler method as temporal discretization.
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\-This model implements a non-\/isothermal two-\/component \-Stokes flow of a fluid solving a momentum balance, a mass balance, a conservation equation for one component, and one balance equation for the energy.
This model implements a non-\/isothermal two-\/component Stokes flow of a fluid solving a momentum balance, a mass balance, a conservation equation for one component, and one balance equation for the energy.
\-Momentum \-Balance\-: \[ \frac{\partial \left(\varrho_g {\boldsymbol{v}}_g\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left(p_g {\bf {I}} - \mu_g \left(\boldsymbol{\nabla} \boldsymbol{v}_g + \boldsymbol{\nabla} \boldsymbol{v}_g^T\right)\right) - \varrho_g {\bf g} = 0, \]
Momentum Balance\-: \[ \frac{\partial \left(\varrho_g {\boldsymbol{v}}_g\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left(p_g {\bf {I}} - \mu_g \left(\boldsymbol{\nabla} \boldsymbol{v}_g + \boldsymbol{\nabla} \boldsymbol{v}_g^T\right)\right) - \varrho_g {\bf g} = 0, \]
\-Mass balance equation\-: \[ \frac{\partial \varrho_g}{\partial t} + \boldsymbol{\nabla}\boldsymbol{\cdot}\left(\varrho_g {\boldsymbol{v}}_g\right) - q_g = 0 \]
Mass balance equation\-: \[ \frac{\partial \varrho_g}{\partial t} + \boldsymbol{\nabla}\boldsymbol{\cdot}\left(\varrho_g {\boldsymbol{v}}_g\right) - q_g = 0 \]
\hyperlink{a00047}{\-Component} mass balance equation\-: \[ \frac{\partial \left(\varrho_g X_g^\kappa\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left( \varrho_g {\boldsymbol{v}}_g X_g^\kappa - D^\kappa_g \varrho_g \boldsymbol{\nabla} X_g^\kappa \right) - q_g^\kappa = 0 \]
\hyperlink{a00070}{Component} mass balance equation\-: \[ \frac{\partial \left(\varrho_g X_g^\kappa\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left( \varrho_g {\boldsymbol{v}}_g X_g^\kappa - D^\kappa_g \varrho_g \boldsymbol{\nabla} X_g^\kappa \right) - q_g^\kappa = 0 \]
\-Energy balance equation\-: \[ \frac{\partial (\varrho_g u_g)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \varrho_g h_g {\boldsymbol{v}}_g - \lambda_g \boldsymbol{\nabla} T - q_T = 0 \]
Energy balance equation\-: \[ \frac{\partial (\varrho_g u_g)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \varrho_g h_g {\boldsymbol{v}}_g - \lambda_g \boldsymbol{\nabla} T - q_T = 0 \]
\-This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit \-Euler method as temporal discretization.
This is discretized using a fully-\/coupled vertex centered finite volume (box) scheme as spatial and the implicit Euler method as temporal discretization.
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\-This model implements laminar \-Stokes flow of a single fluid, solving a momentum balance\-: \[ \frac{\partial \left(\varrho_g {\boldsymbol{v}}_g\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left(p_g {\bf {I}} - \mu_g \left(\boldsymbol{\nabla} \boldsymbol{v}_g + \boldsymbol{\nabla} \boldsymbol{v}_g^T\right)\right) - \varrho_g {\bf g} = 0, \]
This model implements laminar Stokes flow of a single fluid, solving a momentum balance\-: \[ \frac{\partial \left(\varrho_g {\boldsymbol{v}}_g\right)}{\partial t} + \boldsymbol{\nabla} \boldsymbol{\cdot} \left(p_g {\bf {I}} - \mu_g \left(\boldsymbol{\nabla} \boldsymbol{v}_g + \boldsymbol{\nabla} \boldsymbol{v}_g^T\right)\right) - \varrho_g {\bf g} = 0, \]
and the mass balance equation\-: \[ \frac{\partial \varrho_g}{\partial t} + \boldsymbol{\nabla}\boldsymbol{\cdot}\left(\varrho_g {\boldsymbol{v}}_g\right) - q_g = 0 \]
\-This is discretized by a fully-\/coupled vertex-\/centered finite volume (box) scheme in space and by the implicit \-Euler method in time.
By setting the property {\ttfamily Enable\-Navier\-Stokes} to {\ttfamily true} the Navier-\/\-Stokes equation can be solved. In this case an additional term is added to the momentum balance\-: \[ \varrho_g \left(\boldsymbol{v}_g \boldsymbol{\cdot} \boldsymbol{\nabla} \right) \boldsymbol{v}_g \]
This is discretized by a fully-\/coupled vertex-\/centered finite volume (box) scheme in space and by the implicit Euler method in time.
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