Application of a Multi-Objective, Multi-Condition Adjoint Shape Optimization Approach to Reduce Drag for the ADODG CRM Aircraft Model

Robust multi-objective aerodynamic optimization has become necessary within the aerospace community due to ever-increasing efficiency and performance requirements and budgetary and development time constraints. Its importance has been highlighted by the AIAA Aerodynamic Design Optimization Discussion Group (ADODG) in a publication defining a challenge problem for full aircraft optimization (Test Case 5). This paper will present the application of Ansys Fluent and its adjoint gradient-based optimizer (GBO) capability to the problem of modifying (morphing) the wing geometry to maintain lift while also minimizing drag and enforcing zero pitching moment. It is shown that the GBO provides a highly automated workflow which is well-suited to this shape optimization process and highlights some advanced capabilities including the ability to both maximize/minimize specific observables (like drag) and keep other observables fixed or within specific bounds. In addition, parametric mesh morphing capability is demonstrated (as a loosely coupled process) for the problem of rotating the horizontal stabilizer to enforce trim and maintain zero pitching moment. The results will address the optimal GBO workflow using plots of observable changes versus design iteration as well as the overall performance of the final optimized geometry.