Reply To: Wall Function Issue

[kingdomkarl]

Hey!

sorry to reopen this, but at larger Re (=20000), I am having trouble getting a stable setup of my internal pipe-like flow. I let the inlet velocity slowly go up, which works fine. Then I let it run for another flow-through time. Just after that my simulation tends to display unphysical flow patterns at the outlet.

I switched to a convection outlet.:
boundary::set<boundary::InterpolatedConvection>(sLattice, superGeometry, 4);

And use the following WF setting:
const int rhoMethod = 0;
const int fNeqMethod = 1;
const int wallFunctionProfile = 1;
const bool bodyForce = false;
const bool interpolateSampleVelocity = true;
const bool useVanDriest = true;
const T latticeWallDistance = 0.5;
const T samplingCellDistance = 2.5;
const bool movingWall = false;
const bool averageVelocity = false;

My CFL number is 0.005 and tau is 0.500054. The flow at the outlet looks like this: https://postimg.cc/BXRPpRb5

Again, any help is greatly appreciated 🙂