Urgent : Extrenal compressible Flow
 

Hi ,

I want to simulate the external compressible flow over a object approximatley similar to cone with mach number 2.

What is the bounary condition i should use for free boundary ? If as specified by the manual to use the Pressure Far-Field Boumdary Condition the domain 10-20 times of the charecteristic dimension is mandatory ??

I dont have resourses for such a big domain... what is the alternate Boundary Condition I can use

Thanks Venkatesh.V