Flow Structure behind a Wing at High Reynolds Numbers

Abstract

The stereo PIV measurement were performed behind a wing in the plane perpendicular to the flow to study the vortical structures oriented in the streamwise direction, which take place both in suction and pressure sides of the wing. The Reynolds numbers during the experiments in the 3 m wind tunnel range from 0.5 million up to 1.5 million.

Structure of the Wake Behind an Airfoil

“…This precondition is physically justified only in the case of laminar flow, for the turbulent flow it could be applied only on distributions of velocity statistics as mean values and variances, but definitely not on instantaneous situations. In our preceding studies occurrence of streamwise vorticity within the turbulent boundary layer on the suction side of simple airfoil was proved experimentally, see [3,4,[8][9][10][11][12]. However the vorticity appears randomly both in space and time.…”

“…Together with knowledge of presence vorticity component in the measurement plane, which could be learned from previous results (see e.g. [8][9][10][11][12]), the detection method could be considered to be reliable enough.…”

On the global flow-field dynamics around an airfoil

“…Our research group published recently several experimental studies on 3D instantaneous structure of the flow around a simple airfoil, e.g. [5,6,9,10,11]. The presented study is oriented on the existence of spanwise-oriented structures and their dynamics and merging with each other along the profile chord.…”