[Ry10]

For the QuickStart files I got the lift and drag gradients to match up fairly well between adjoint method and finite difference using a Mach number of 0.8. However, the lower the mach number the farther apart the drag gradients got between adjoint and finite difference. For a Mach number of 0.15 the lift gradients were still fine but the drag gradients were orders of magnitude off and even in some cases the wrong sign. Why does the accuracy of the drag gradients compared to finite difference depend so much on the Mach number? And how can I get good gradients at low Mach numbers? I have tried the incompressible TestCases but I haven't been able to get the drag gradients to match either.