[laptmu]

Dear Everyone,

I am new in OpenFoam, now I am building a solver (PisoFoam2) based on PisoFoam.
In the momentum equation of PisoFoam is divided by rho. But I would like to build a solver that considers rho in the momentum equation, and it is not compressible.
This is my UEqn code.
fvVectorMatrix UEqn
(
fvm::ddt(rho, U) + fvm::div(rhoPhi, U)
+ turbulence->divDevRhoReff(U)
==
fvOptions(rho, U)
);
UEqn.relax();

fvOptions.constrain(UEqn);

if (piso.momentumPredictor())
{
solve(UEqn == -fvc::grad(p));

fvOptions.correct(U);
}
I defined rho and rhoPhi in createFields.H, and in running case I changed the pressure file p to kg/m.s^2.

I compiled successfully but when I run it showed that

--> FOAM FATAL ERROR:
incompatible dimensions for operation
[U[1 -2 -2 0 0 0 0] ] + [U[0 1 -2 0 0 0 0] ]


Please help me to solved this errors.