Discussion Forum

I want to build a model which requires to couple the mass transportation and rotating machinery of the fluid flow. I trying to approach that using 3 steps: 1. Solve the fluid flow in a stationary study using frozen rotor. 2. Use the static frozen rotor solution as the initial values to solve a time dependent solution of fluid flow. 3. Use the time dependent flow solution to solve the mass transport in a separate study. I met a problem in defining the inlet flow and outlet flow in fluid flow interface (SPF). If I define the inlet and outlet boundary in fluid flow at step 1, COMSOL fails to give me a solution. I can solve the rotation of the fluid without the inlet and outlet boundary definition. But then I will meet problem when I am trying to couple the mass. Because I have to define the inlet and outlet in mass interface. That is can not be coupled with the flow interface. I got a uniform distribution of species everywhere, which is different from my expectation that higher concentration of species near inlets and lower around the space. I really need to know how to define the inlets and outlets in rotating fluid. I will be really appreciative if anyone can help with that.