Divergence at high U_LB and real physical velocity


After running the example externalFlowAroundObstacle with given parameters, i was trying to increase the inlet velocity/nu. When i increase the inlet velocity the time step becomes small correspondingly and if i try to increase dt (to reduce simulation time) by increasing the uLB, the simulation becomes unstable and diverges. I want to test the model for high Re of the order 200000. The time step also depends upon u and uLB

dx = ly / (resolution - 1.0);
dt = (uLB/inletVelocity) * dx;
T nuLB = nu * dt/(dxdx);
omega = 1.0/(DESCRIPTOR::invCs2

I understand that LBM requires uLB to be as low as possible. But i do not know how to do the simulation i want. So is there anyother way to increase the physical inlet velocity and keep the number of iterations/time step (dt) low without affecting the stability of LBM?

I would be extremely thankful if some one can throw some light upon this. Thank you very much for your help.

Kind regards,