Abstract: Quantitative and visual data of artificially forced instabilities have been acquired in a flat plate boundary layer in air. For the first time the Particle Image Velocimetry (PIV) allows the recording of a complete velocity field instantaneously. With this technique quantitative data have been obtained within the boundary layer also very close to the wall. By using a light sheet technique it was possible furthermore to obtain visual data. Reproducible and constant conditions in the development of the instabilities are achieved by forcing the boundary layer with well controlled disturbances. These disturbances are generated with an arrangement for acoustic excitation.!11
展开▼
