A POD-based reduced order modeling approach for the efficient computation of high-lift aerodynamics

Kurzfassung

In this paper we propose a methodology for the efficient and robust computation of the aerodynamics of high-lift configurations. A reduced-order modeling approach is considered, based on the proper orthogonal decomposition (POD) of a set of high-fidelity CFD solutions or snapshots from which a reduced basis is evaluated. From this reduced-order model (ROM), a solution is predicted at an angle of attack which is outside the space spanned by the POD basis vectors. The ROM solution is subsequently used to initialize the flow solver for an accurate calculation of the aerodynamics at the same flow condition. This procedure is conducted recursively for a series of angles of attack, whereby for each and every ROM prediction, the snapshots set is augmented with the latest CFD computed flow solution. Using this methodology, a considerable reduction in the total number of iterations to reach the steady-state solution is observed when compared with conventional computational techniques used in industry for a series of computations such as drag polar computations. Ultimately, a preliminary investigation is conducted on the behavior of the reduced-order modeling approach at static stall angles of attack where aerodynamic hysteresis may occur and the aerodynamic coefficients are found to be multiple-valued functions of the angle of attack.