It is possible to use different discretization schemes for the flow and the adjoint solvers in ANSYS Fluent. This is often recommended to have a higher accuracy for the flow solver and better stability for the adjoint solver. Having different discretization schemes can have some adverse effect on the calculation of the value of the observable (see also solution 2058309) but it offers a great advantage with respect to stability. The attached document shows examples that you can better judge the influence of using different schemes for flow and adjoint solvers.

Attachments:
1. 2059054.pdf