Conditional averaging on volumetric velocity fields for analysis of the pseudo-periodic organization of jet-in-crossflow vortices

Volumetric velocimetry measurements have been performed on a round jet in crossflow (JICF). Two kind of conditional averaging process are presented : a global conditional average (GCA) and a local conditional average (LCA). Vortices crossing the JICF symmetry plane are used to quantify the jet pseudo-periodicity leading to the GCA and LCA definitions. Because they make possible to improve the velocity field resolution as well as to significantly reduce the experimental noise, these conditional averages are an interesting and efficient way to study the instantaneous swirling structures of this instantaneous flow.