Hi, I have a very simple model with just several inlets and one outlet. However, it doesn't converge when I run it. I used prostar to create the mesh. Can anyone please tell me what could be the problem? I used UD scheme. I checked everything before I run it and I didn't find any error. Thank you.

There could be many reasons. Without more information about your model its really hard to say.

Is UD appropriate for your flow? If your flow is highly dependent on downstream conditions try a different scheme like MARS

Have you selected the appropriate turbulence models?

How many iterations have you let it run?

Are the residuals oscillating, decreasing, or increasing?

define "not converging" better....it could be one of a load of things..if you are using an outlet, try a pressure boundary instead

Thanks Adam and Ben. I think the problem is fixed now. I was using laminar model earlier. Now I swithched it to high reynolds # k-epsilon turbulence model since the Reynolds # in the simulation is high. It was oscillating earlier. Now it is converging after 10,000 iterations. Thank you.