[gharek]

Hi everyone,

I'm having some issues with negative velocity boundary conditions with LES in pimpleFoam. I'm simulating an ambient air flow over a box which has a couple of patches with negative velocity boundary condition representing 'suction'. RANS (simplefoam) solver gives reasonable results, but when using the same boundary condition in LES mode (pimpleFoam), solution is not reasonable. Very high velocities were predicted near the suction patches. The solver eventually blew up.

boundary conditions: U (fixedValue negative), p (zeroGradient)

I have tried using fixedFluxPressure for p instead of zeroGradient, flowRateInletVelocity instead of fixedValue for U, the issue persists. I have also tried ramping the velocity and/or flowrate, the issue persists.

Other things I've tried:

• increasing number of pimple outer loop
• reducing relaxation factors

The issue persists.

I have also reviewed a related post here: Velocity boundary condition: negative value (suction)

Does anyone have any suggestions/ideas as to what I may have missed or done wrong?

Cheers.