Towards best-practice guidelines for POD-based reduced order modeling of transonic flows

Abstract

Via the proper orthogonal decomposition (POD) solving the full-order governing equations of Computational Fluid Dynamics (CFD) is replaced by determining a suitable linear combination of POD basis vectors. As a consequence, only a low-order vector of POD coefficients has to be determined in order to obtain an approximate flow solution. There exist various methods for computing POD coefficients, among them interpolating and solving low-order PDE systems. For stationary aerodynamics, a POD-based reduced order model (ROM) can be obtained by minimizing the defect in the governing equations of fluid dynamics of the approximate POD solution. Following this approach, in this paper, a number of fundamental options in setting up the ROM process are identified, which affect its overall performance. Based on an exhaustive testing of all the possible options by means of predicting surface pressure distributions for the NACA 64A010 airfoil in the transonic flow regime, best-practice guidelines are deduced.