COMPUTATIONAL SIMULATION OF DYNAMIC STALL ON THE NLR 7301 AIRFOIL

Abstract

The dynamic stall behavior of the supercritical NLR 7301 airfoil is analyzed with a 2-D thin-layer Navier–Stokes code. The code solves the compressible Reynolds-averaged Navier-Stokes equations with an upwind biased numerical scheme in combination with the Baldwin–Lomax or the Baldwin–Barth turbulence models. The effect of boundary layer transition is incorporated using the transition length model of Gostelow et al. The transition onset location is determined with Michel's formula or it can be specified as an input parameter. The two turbulence models yield significantly different steady-state lift coefficients at incidences greater than 8°. The use of the one-equation Baldwin–Barth model together with the Gostelow transition model is found to give substantially better agreement with the experimental data of McCroskeyet al. than the Baldwin–Lomax model. Also, the unsteady computations are strongly affected by the choice of the turbulence model. The Baldwin–Barth model predicts the lift hysteresis loops consistently better than the algebraic turbulence model. However, the one-equation model improves the prediction of the moment hysteresis loops only for one test case.