I have problem in meshing the flow area around AHMED body in GAMBIT. Does anyone have clues.

can you elaborate further?

The flow domain I am taking as per research papers is rectangular with dimensions of 8L*5L in case of 2D. As I use the face meshing schemes, the mesh is either not generated fully or is not generated in a uniform manner. The test case is to be analysed for wake production at various backlight angles and also underbody flow mechanisms.

Note that Ahmed body cannot be analysed as 2D case. See the front of the ahmed body. It has curved radius from all 4 sides not just from 2 sides. Had it been in 2 sides only, you could have modelled it like a 2D problem. Better to create a 3D model in GAMBIT.

Most of the research papers have also simulated a 2D case; ofcourse it is far from reality but helps in understanding mechanisms of wake flows around vehicles. when taken the central plane it will have curvature of two edges only in 2D.