Automatic particle tracking velocimetry beneath a wind-stressed wavy water surface with image processing

The turbulent flow in water close to the wavy wind-stressed water surface has been measured in a large circular wind-water tunnel with a low cost image processing system, using a CCD camera. The flow field beneath the moving air-water interface is being visualized by small particles illuminated by a thin light sheet. The velocity vectors have been determined by image sequence analysis of up to 32 binary images. Since every particle is traced along its full path within the light sheet, both the Eulerian and the Lagrangian velocity fields can be calculated. Simultaneously, the wave profile is determined.