Hi guys! As I´m very happy with the support in this forum, i`d like to share my cfd validations with the Ahmed-Body, you might know. Maybe you can just share your opinion on this.
So, I´m using cfd for a car simulation project, so i just took the exact same settings i use for the ahmedbody Validation. I generally use the hex-dominant parametric mesher! And i was pretty happy, that i received a drag coefficient of 0,323 with a mesh of 1,8mil! (Experimental measures ended with a cd of 0,298). So 8% failure seemed pretty nice for me.
I had a quick look into both projects, and I realized that the finer mesh actually resulted in a coarser surface mesh due to difference in meshing algorithm although number of cells are higher. This probably yield your results to deviate even further from the experimental results. Surface fineness is very important while calculating the drag and lift coefficients, because these forces are calculated based on pressure and stress values in each cell.
I would recommend you to use local element refinements while refining your mesh in such external aerodynamics application rather than refining the boundaries. It should give you a more accurate mesh sensitivity study.
