From ff70994583ce427df9465a5f8af65fea76574625 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20Gr=C3=BCninger?=
<christoph.grueninger@iws.uni-stuttgart.de>
Date: Thu, 6 Oct 2016 15:31:23 +0200
Subject: [PATCH] Half number of std::pow calls in thermal conductivity laws
---
.../2p/thermalconductivityjohansen.hh | 3 ++-
.../2p/thermalconductivitysomerton.hh | 6 +++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/dumux/material/fluidmatrixinteractions/2p/thermalconductivityjohansen.hh b/dumux/material/fluidmatrixinteractions/2p/thermalconductivityjohansen.hh
index 975d8b3bc1..3434a8f68a 100644
--- a/dumux/material/fluidmatrixinteractions/2p/thermalconductivityjohansen.hh
+++ b/dumux/material/fluidmatrixinteractions/2p/thermalconductivityjohansen.hh
@@ -128,7 +128,8 @@ public:
const Scalar kappa = 15.6; // fitted to medium quartz sand
const Scalar rhoBulk = rhoSolid*porosity;
- const Scalar lSat = std::pow(lambdaSolid, (1.0 - porosity)) * std::pow(lambdaW, porosity);
+ // lambdaSolid^(1-porosity) * lambdaW^porosity =
+ const Scalar lSat = lambdaSolid * std::pow(lambdaW / lambdaSolid, porosity);
const Scalar lDry = (0.135*rhoBulk + 64.7)/(rhoSolid - 0.947*rhoBulk);
const Scalar Ke = (kappa*satW)/(1+(kappa-1)*satW);// Kersten number, equation 13
diff --git a/dumux/material/fluidmatrixinteractions/2p/thermalconductivitysomerton.hh b/dumux/material/fluidmatrixinteractions/2p/thermalconductivitysomerton.hh
index 1f27e8e056..9bebe3b259 100644
--- a/dumux/material/fluidmatrixinteractions/2p/thermalconductivitysomerton.hh
+++ b/dumux/material/fluidmatrixinteractions/2p/thermalconductivitysomerton.hh
@@ -119,9 +119,9 @@ public:
const Scalar rhoSolid = 0.0 /*unused*/)
{
const Scalar satW = std::max<Scalar>(0.0, sw);
- // geometric mean
- const Scalar lSat = std::pow(lambdaSolid, (1.0 - porosity)) * std::pow(lambdaW, porosity);
- const Scalar lDry = std::pow(lambdaSolid, (1.0 - porosity)) * std::pow(lambdaN, porosity);
+ // geometric mean, using ls^(1-p)*l^p = ls*(l/ls)^p
+ const Scalar lSat = lambdaSolid * std::pow(lambdaW / lambdaSolid, porosity);
+ const Scalar lDry = lambdaSolid * std::pow(lambdaN / lambdaSolid, porosity);
return lDry + std::sqrt(satW) * (lSat - lDry);
}
--
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