How to determine a steady flow?
 

Currently, I am simulating the unsteady air flow in a gas turbine enclosure. How could I know whether the flow has become steady or not?

Re: How to determine a steady flow?
 

You can set up a macro to record the turbulent viscosity, say every 50 iterations, and leave the simulation running for say 500-1000 iterations. If you have an animation package, paint-shop pro, then you will be able to animate the above 10 or more slides to see any wake or 'unsteadiness' in the flow field. It is a brilliant way to visualise the flow field in a global manor. Of course it does not provide any mathematical verification of a steady flow, it is purely visual, however, will there really be any purely steady flow?

Andy

Re: How to determine a steady flow?
 

if you don't have time to see/make the animations, try to monitor the gradient of solution parameters at some critical points.

DC

Re: How to determine a steady flow?
 

What do you mena by the 'gradient' of solution parameter?

Re: How to determine a steady flow?
 

for example gradient of velocity component at some critical points. dv/dx for example