Dynamic Stall and its Passive Control Investigations on the OA209 Airfoil Section

Abstract

Within the joint DLR/ONERA project “Dynamic Stall” it was decided to select the ONERA OA209 airfoil section as a candidate for common comprehensive numerical as well as experimental investigations. While at ONERA the low speed aspects have mainly been addressed and experiments have been carried out in the F2-wind-tunnel facility in Fougat, France, DLR has concentrated on investigations in the compressible flow regime starting at Ma=0.3 and reaching into the transonic flow regime up to Ma=0.75. In the present paper recent experimental investigations are presented which have been conducted in the 1mx1m transonic wind tunnel facility DNW-TWG located at DLR-Göttingen in a two weeks test-campaign during October/November 2004. The tests have been done in a joint effort between the DLR Institute of Aerodynamics and Flow Technology (AS) and the DLR Institute of Aeroelasticity (AE) both located at the DLR Site in Göttingen, Germany. Two main topics have been addressed during the test campaign: 1) Steady, Light Stall and Deep Stall investigations on the clean blade section, 2) Exploratory studies of passive control during dynamic stall by means of miniature leading edge vortex generators, LEVOG’s. The blade model with 0.3m chord and 1m span (arranged between wind tunnel side walls) was equipped with 45 pressure sensors (Kulites) along the mid-section of the model. In addition to unsteady pressure measurements PIV recordings have been taken for each test point. Corresponding numerical calculations have been done on the basis of a 2D-time accurate Navier-Stokes code for comparisons with the experimental data.