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

TL;DR

This paper introduces conditional averaging techniques applied to volumetric velocimetry data of a jet in crossflow, enhancing the analysis of vortex organization and flow structures by reducing noise and increasing resolution.

Contribution

It presents global and local conditional averaging methods for volumetric velocity fields to better analyze vortex organization in jet-in-crossflow flows.

Findings

Conditional averaging improves flow field resolution.

Reduces experimental noise in volumetric velocimetry data.

Reveals pseudo-periodic vortex organization.

Abstract

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.