Extensive characterization of a high Reynolds number decelerating boundary layer using advanced optical metrology

TL;DR

This study provides a comprehensive optical measurement-based analysis of large-scale turbulent structures in a high Reynolds number adverse pressure gradient boundary layer, revealing detailed flow characteristics and wall-shear stress variations.

Contribution

It introduces advanced optical metrology techniques, including large-scale PIV and stereoscopic measurements, to characterize complex boundary layer structures at high Reynolds numbers.

Findings

Identification of large-scale turbulent structures

Detailed wall-shear stress fluctuation data

Insights into boundary layer dynamics under adverse pressure gradient

Abstract

An experiment conducted in the framework of the EUHIT project and designed to characterize large scale structures in an adverse pressure gradient boundary layer flow is presented. Up to 16 sCMOS cameras were used in order to perform large scale turbulent boundary layer PIV measurements with a large field of view and appropriate spatial resolution. To access the span-wise / wall-normal signature of the structures as well, stereoscopic PIV measurements in span-wise/wall-normal planes were performed at specific stream-wise locations. To complement these large field of view measurements, long-range micro-PIV, time resolved near wall velocity profiles and film-based measurements were performed in order to determine the wall-shear stress and its fluctuations at some specific locations along the model.