Effects of strong adverse pressure gradients and incident wakes on transition and calming

Abstract

At a previous meeting results based on wavelet analysis demonstrated similarities between triggered turbulent spots and the turbulent patches caused by wake interactions on compressor and turbine blading[1]. Hughes and Walker[2] went further and used wavelet conditioning to identify the prevalence of Tollmien-Schlichting instability phenomena in the flow over axial flow compressor blades. In the current investigation transition phenomena occurring in axial flow compressors are simulated on a larger scale to provide further evidence on the similarities between turbomachinery and wind tunnel flows. The applicability of the intermittency-based approaches to the closure of laminar separation bubbles is demonstrated. The spacing between impinging wakes is systematically varied and it is found that the calmed region acts to suppress turbulence, even for closely spaced wakes. © 2006 Springer.