[m2montazari]

Dear everyone,
I'm a master student and I had chosen OpenFoam as the cfd software for my thesis. I want to find the flow noise induced and specifically the noise of cavitation bubbles when they collapse. as first step I tried to find the turbulence noise by running dnsfoam. I encountered some problems and these are the main questions I have:
1- why the grid size on all of edges must be a power of 2? is this mean that i cant have an unstructured or multiple-block structured grid? how about multiple connected regions like a domain around a body?
2- what is the turbulence constants in turbulenceProperties?(I know they are just for initialize the turbulence but I don't know how can I find their value for my case)
3- what is the real order of discretization of equations? is it just as I choose in fvScheme->interpolation like linear=2,QUICK=4,...?

I'm looking forward for someones help...
Mohammad