Wind tunnel investigation of flow around a rotor in ground effect

This paper presents results of a wind tunnel investigation of the wake below a model rotor in ground effect. The wind tunnel used was equipped with a rolling road, and the experiments assessed the influence of the moving ground boundary condition on the flow. Particle Image Velocimetry was used to investigate the structure of the wake, and it was observed thatt he moving ground boundary condition had a remarkable effect on the wake actoss a wide range of advance ratios. The moving ground reduces the size of the wake and moves it closer to the rotor, and the detailed distribution of vorticity within the wake is also affected.