Sensitivity of crossflow surfacetransitionroughnessto free-stream conditions and

The present work is an experimental investigation of stationary crossflow (CF) instability-induced transition of the boundary layer over a 45°swept wing, under varying free-stream turbulence, surface roughness, angle of attack and Reynolds number. Key topological features of the transition front, such as the mean transition location and the...

Swept-wing transition control using DBD plasma actuators

In the present work, laminar flow control, following the discrete roughness elements (DRE) strategy, also called upstream flow deformation (UFD) was applied on a 45^◦ swept-wing at a chord Reynold’s number of Re_c = 2.1 · 10⁶ undergoing cross-flow instability (CFI) induced transition. Dielectric barrier...

Secondary Stability Analysis of Crossflow Vortices using BiGlobal Theory on PIV Base Flows

Time-resolved PIV investigation of the secondary instability of cross-flow vortices

Time-resolved PIV measurements of the secondary instability modes of cross-flow vortices are presented. Measurements are performed on a large scale 45o swept wing at chord Reynolds number of 2.17 million in a low turbulence wind-tunnel facility. Using acquisition frequencies of 20 kHz, the present study is the first experimental demonstration...

Flow visualization of swept wing boundary layer transition

In this work the flow visualization of the transition pattern occurring on a swept wing in a subsonic flow is presented. This is done by means of fluorescent oil flow technique and boundary layer hot-wire scans. The experiment was performed at Reynolds number of 2:15 . 106 and at angle of attack of -3º. At these conditions, three different flows...

High-speed PIV analysis of trailing edge aeroacoustics

Tonal noise generated by airfoils observed at low to moderate Reynolds numbers is related to laminar boundary layer instabilities, which has lead to the term laminar boundary layer instability noise. The particular features of the acoustic spectrum have been discussed and a number of theories have been proposed in literature over the past 50...

High-speed PIV analysis of trailing edge aeroacoustics

Tonal noise generated by airfoils observed at low to moderate Reynolds numbers is related to laminar boundary layer instabilities, which has lead to the term laminar boundary layer instability noise. The particular features of the acoustic spectrum have been discussed and a number of theories have been proposed in literature over the past 50...