From cc002f450d608b01c422b530575b703704e07cb1 Mon Sep 17 00:00:00 2001
From: Lars von Wolff <lars.von-wolff@ians.uni-stuttgart.de>
Date: Sat, 19 Feb 2022 12:51:39 +0100
Subject: [PATCH] Fixed Momentum Transport in weak formulation

---
 dune/phasefield/localoperator/fem_ff_chns_navierstokes.hh | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dune/phasefield/localoperator/fem_ff_chns_navierstokes.hh b/dune/phasefield/localoperator/fem_ff_chns_navierstokes.hh
index 0572f05..686e2d8 100644
--- a/dune/phasefield/localoperator/fem_ff_chns_navierstokes.hh
+++ b/dune/phasefield/localoperator/fem_ff_chns_navierstokes.hh
@@ -197,10 +197,11 @@ template<typename Param, typename CHGFS, typename CHContainer, typename NSGFS, t
 
               //RF lambda = 3;
               const auto v_nabla_v = v * jacv[k];
+              const auto gradxi_nabla_v = gradxi * jacv[k];
 
               r.accumulate(child(vspace,k),i, factor*(
-                              ((rho+rhoOld)/2*v[k]-rhoOld*vOld[k])*vphi[i]/param.time.dt          //TimeEvolution
-                              + ( rho* v_nabla_v  + param.mobility.eval(pf)*gradxi[k]*(param.phys.rho_1-param.phys.rho_2)  )* vphi[i] // Momentum transport
+                              rho*(v[k]-vOld[k])*vphi[i]/param.time.dt          //TimeEvolution
+                              + ( rho* v_nabla_v  + param.mobility.eval(pf)*gradxi_nabla_v*(param.phys.rho_1-param.phys.rho_2)  )* vphi[i] // Momentum transport
                               - p * gradvphi[i][0][k]            //Pressure
                               + param.phys.mu * (jacv[k]*gradvphi[i][0]) //+vphi[i]*(jacv[k]*gradpf)   )  //Viscosity
                               - rho*g[k]*vphi[i]                //Gravitation
-- 
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