Navier-Stokes: computing 3D velocity gradient

[Watchmojo]

I am interested to add turbulence models in the NS solver. As the first step, the velocity gradient tensor needs to be calculated. I did the following:

Step 1: added std::vector<ParGridFunction> du_gf in the naver_solver class, and initialized using
du_gf.resize(vfes->GetVDim());
for (auto it = du_gf.begin(); it != du_gf.end(); it++)
it->SetSpace(vfes);

Step 2: "Hijacked" ComputeCurl3D and made it a new function like this:
void NavierSolver::ComputeGrad3D(ParGridFunction &u, std::vector<ParGridFunction> &du)

The navier_solver.hpp navier_solver.cpp are attached here.

1. Would you please comment?
2. Is the vector du at the end of this function in the physical or function space?

navier_solver.zip

[jandrej]

I won't review the attached file.

To compute the gradient of a vector valued GridFunction wouldn't the method

   void GetVectorGradient(ElementTransformation &tr, DenseMatrix &grad) const;

suffice?

[suqingji]

Hi, Dear prof.
Have you finished turbulence model in ns solver.
thanks.