SMALL DISTURBANCE NAVIER-STOKES COMPUTATIONS FOR LOW ASPECT RATIO WING PITCHING OSCILLATIONS

摘要

For dynamic production aeroelastic analysis in the transonic speed range a computational uid dynamics (CFD) method based on the small disturbance Navier-Stokes equations can serve as a reasonable alternative to one realizing the Reynolds-averaged Navier-Stokes (RANS) equations' time domain solution: Its dynamically linear approach promises signi cantly decreased computation cost in the prediction of unsteady aerodynamic loading while retaining the latter's delity to a high degree. In this regard, research conducted at the Technische Universit ?t München has resulted in the CFD method FLM-SD.NS. Further substantiating its application readiness, computations for harmonic pitching oscillations of the NASA clipped delta wing are presented. Test cases are characterized by shocks of varying strength and range of motion, as well as leading edge vortex (LEV) formation. Overall, results are in good agreement with dynamically fully nonlinear solutions provided by the comparative RANS solver FLMNS, as well as available experimental data. Reductions in computation time up to an order of magnitude in relation to FLM-NS are observed. Limitations of the small disturbance approach, however, become apparent for the LEV case, where higher-order harmonics are far less negligible in the ow's response to the excitation.