Holographic interferometry versus stereoscopic PIV for measuring out-of-plane velocity fields in confined flows

This paper describes and compares holographic interferometry and stereoscop ic PIV as techniques for measuring out-of-plane velocity fields. Most relev ant aspects in both techniques are revised. Special attention is paid to th e specific problems encountered in confined flows. The presence of walls li miting the flow prevents the use of some optical configurations for the pho tographic and holographic recordings. Several optical configurations have b een analysed. Experiments have been carried out in a small Rayleigh-Benard convective cell. Results obtained for the out-of-plane component with both techniques are compared and discussed.