NUMERICAL INSTABILITY OVER THE SWIRLING VANES
 

Hi!

Has anyone observed the numerical instability over the swirling vanes. What we have is the flow over a set of vanes. We have pressure inlets and one pressure outlet. What we are observing is the mass flow rate through the pressure outlet is oscillating in a sinusoidal fashion.

Has anyone come across this kind of situation and has any comments/suggestions. We have tried with lowering the under relaxation factors. Even to a small number like 0.001, the mass flow rate is still sinusoidal.

Re: NUMERICAL INSTABILITY OVER THE SWIRLING VANES
 

Are you doing a transient or steady state calculation. By that I mean, are you solving

dq/dt = RHS

or

RHS = 0?

Asked another way: are you sure that your problem doesn't actually have a periodic (shedding) solution?

Re: NUMERICAL INSTABILITY OVER THE SWIRLING VANES
 

I am using RHS=0

It is solved in steady state