Adjoint Method for Aerodynamic Shape Improvement in Comparison with Surface Pressure Gradient Method

Understanding the flow characteristics and, especially, how the aerodynamic forces are influenced by the changes in the vehicle body shape, are very important in order to improve vehicle aerodynamics. One specific goal of aerodynamic shape optimization is to predict the local shape sensitivities for aerodynamic forces. The availability of a reliable and efficient sensitivity analysis method will help to reduce the number of design iterations and the aerodynamic development costs. Among various shape optimization methods, the Adjoint Method has received much attention as an efficient sensitivity analysis method for aerodynamic shape optimization because it allows the computation of sensitivity information for a large number of shape parameters simultaneously. In the present study, the discrete adjoint equations to the ANSYS-Fluent pressure-based flow solver are formulated and solved in order to provide the aerodynamic shape sensitivities on the drag force for a simplified vehicle shape. The present study is intended to provide insights for aerodynamic shape improvement by observing the shape sensitivities and comparing the results for the diagnostic method based on the surface pressure gradients in the stream-wise and the transverse directions [ 1 ].