I'm doing compressible inviscid turbulent calculations on an aeroplane - unstructured tetrahedral mesh. My domain is defined as a large cube (length of the sides is 200m) in which the plane is placed in the center. The question is which boundary conditions to apply on the sides of this large cube. So far I have applied inlet on 5 sides (because I need to "fly" the plane with side slip and pitch) and outlet on one side (behind the plane). However this results in a pressure rise near the inlets which is unwanted.

Thanks for your help.

Martin

Your domain seems large enough. Why can't you use inlet/outlet with the side walls as slip? Yes, you would get a pressure rise from the front of the plane, but this should not extend to the inlet if your more the 3 plane distances in front.

The side walls should be far enough away not to have a significant influence either.

Fred

Thanks for your interest Fred.

The reason why I cannot use slip walls is that I need the plane to fly a little sideways (fx. when landing with side wind). That means I have to use inlets on (at least some of) the sides in the cube. If I use slip walls they will not be parallel to the flow and therefore introduce some unwanted boundary conditions. I hope that answers your question and that you have a suggestion of what would be reasonable to do.

I had a similar problem which i solved by using pressure boundaries at the sides, this of course if you believe that these boundaries are far enough to be in an almost undisturbed region. in my case it worked because it allowed for a little flux out of these sides. I should mention that you should manually adjust the outlet flux to account for this side flux.

dear fred

i'd like to have some fortran programs

about the boundary conditions for the

cylinderical coordinates,and cartizian

coordinates for the flow of air in ahori-

zontal pipe using the TDMA METHOD OF SOLUTION.

YOURS M.ELHADY