PIV of the flow over a NREL S826 airfoil subjected to different ice accretions

Abstract

The flow field over a NREL S826 airfoil subjected to different ice accretions has been investigated by particle image velocimetry for angles of attack ranging from -4° to 16°. The results have been compared to previously acquired force measurements. For streamlined ice accretions, increased surface roughness and changes to the combined airfoil-ice geometry lead to reduced aerodynamical performance of the airfoil. However, the streamlined ice accretions might act as leading edge flaps at high angles of attack, delaying stall. For the horn ice accretion, a large separation bubble occurs behind the horn reducing the performance of the airfoil, and initiating stall at a lower angle of attack compared to the other cases.