Comparisoin of PIV data with hot-wire measurements and calculations obtained for instabilities in a flat plate boundary layer

Kurzfassung

Artificially forced instabilities were studied experimentally in the transition region of a Blasius boundary layer in air by means of Particle Image Velocimetry (PIV) and hot-wire anemometry. Reproducible and constant conditions in the development of the instabilities were achieved by forcing the boundary layer with well controlled disturbances. The arrangement for artificial excitation provides the possibility to generate the fundamental and the subharmonic transition type as well. Out of the instantaneous velocity fields of the PIV recordings integral quantities were obtained by means of data analysis. These integral data were compared with data achieved by the hot-wire measurements and calculations (Numerical Simulation). The procedure itself to obtain integral data out of the PIV recordings and the limiting parameters of this procedure will be presented.