Unsteady CFD simulation of the NASA common research model in low speed stall

Abstract

In advance of cryogenic time-resolved PIV measurements in the European Transonic Windtunnel ETW unsteady CFD simulations of the NASA Common Research Model have been carried out. In the observed high Reynolds number and low Mach number flow regime a pressure induced boundary layer separation occurs on the main wing at high angles of attack. In steady RANS simulations the development of the separation over the wing surface was investigated and found to begin on the mid-board sections. For analysis of the unsteadiness of the wake flow and the impact on the htp an URANS calculation was conducted for a high angle of attack case. Calculated spectra of surface and wake pressures are presented. The presence of a spectral gap in the URANS simulations is discussed on the basis of the resolved fluctuations’ spectra and a modelled turbulent energy spectrum derived from turbulence model entities. Finally an overview of computational resources spent and computational performance achieved within the SCBOPT project is given.