//--------------------------------------------------//
//- rotate fields
{
Info << "Rotating fields" << endl;
F = I + DF;
//U += DU;
Usolid += DU;
//epsilon += DEpsilon;
sigma += DSigma;
//volTensorField Finv = inv(F);
J = det(F);
rho = rho/J;
//epsilon = symm(Finv.T() & epsilon & Finv);
sigma = 1/J * symm(F & sigma & F.T());
}