[components] Replace std::pow were possible

dumux/material/components/air.hh

@@ -143,7 +143,8 @@ public:
             1.16145*std::pow(Tstar, -0.14874) +
             0.52487*std::exp(- 0.77320*Tstar) +
             2.16178*std::exp(- 2.43787*Tstar);
-        Scalar mu = 40.785*Fc*std::sqrt(M*temperature)/(std::pow(Vc, 2./3)*Omega_v);
+        Scalar mu = 40.785 * Fc * std::sqrt(M * temperature)
+                    / (std::cbrt(Vc * Vc) * Omega_v);
 
         // convertion from micro poise to Pa s
         return mu/1e6 / 10;
@@ -152,14 +153,12 @@ public:
     // simpler method, from old constrelAir.hh
     static Scalar simpleGasViscosity(Scalar temperature, Scalar pressure)
     {
-        Scalar r;
         if(temperature < 273.15 || temperature > 660.)
         {
             DUNE_THROW(NumericalProblem,
                 "simpleGasViscosity: Temperature out of range! (T = " << temperature << " K)");
         }
-        r = 1.496*1.E-6*std::pow(temperature,1.5)/(temperature+120.);
-        return (r);
+        return 1.496e-6 * std::cbrt(temperature * temperature) / (temperature + 120.);
 
     }
 

dumux/material/components/h2o.hh

@@ -867,7 +867,7 @@ private:
     static constexpr Scalar heatCap_p_Region1_(Scalar temperature, Scalar pressure)
     {
         return
-            - pow(Region1::tau(temperature), 2 ) *
+            -1 * Region1::tau(temperature) * Region1::tau(temperature) *
             Region1::ddGamma_ddTau(temperature, pressure) *
             Rs;
     }
@@ -877,10 +877,10 @@ private:
     {
         Scalar tau = Region1::tau(temperature);
         Scalar num = Region1::dGamma_dPi(temperature, pressure) - tau * Region1::ddGamma_dTaudPi(temperature, pressure);
-        Scalar diff = pow(num, 2) / Region1::ddGamma_ddPi(temperature, pressure);
+        Scalar diff = num * num / Region1::ddGamma_ddPi(temperature, pressure);
 
         return
-            - pow(tau, 2 ) *
+            -1 * tau * tau *
             Region1::ddGamma_ddTau(temperature, pressure) * Rs +
             diff;
     }
@@ -925,7 +925,7 @@ private:
     static constexpr Scalar heatCap_p_Region2_(Scalar temperature, Scalar pressure)
     {
         return
-            - pow(Region2::tau(temperature), 2 ) *
+            -1 * Region2::tau(temperature) * Region2::tau(temperature) *
             Region2::ddGamma_ddTau(temperature, pressure) *
             Rs;
     }
@@ -938,7 +938,7 @@ private:
         Scalar num = 1 + pi * Region2::dGamma_dPi(temperature, pressure) + tau * pi * Region2::ddGamma_dTaudPi(temperature, pressure);
         Scalar diff = num * num / (1 - pi * pi * Region2::ddGamma_ddPi(temperature, pressure));
         return
-            - pow(tau, 2 ) *
+            -1 * tau * tau *
             Region2::ddGamma_ddTau(temperature, pressure) * Rs
             - diff;
     }