Two differebt implementation but different results
 

Hi FOAMers
I change this part of icoFoam code:
fvVectorMatrix UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)
);

solve(UEqn == -fvc::grad(p));
to:
fvVectorMatrix UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)
+ fvc::grad(p)
);

solve(UEqn);
but in the second case I got divergence.
Can any one tell me what is the problem?
Best regards