Application potential of Doppler global velocimetry in compressible flows

Abstract

Doppler global velocimetry (DGV) provides planar three-component velocity data at a high spatial resolution. As an intensity-based technique there is no need to resolve the light-sheet illuminated particles directly and therefore is a viable alternative to PIV in applications with difficult optical access. Two recent applications of DGV in compressible flows are selected to give an impression of the technique’s current state-of-the-art. The flow field downstream of winglet devices was measured in the transonic cryogenic flow of the ETW at pressures up to 3.8 bar and free stream Mach numbers up to 0.88. The second example describes the use of DGV for flow studies inside a motored piston engine operating at 3000 rpm. In both cases fiber-based illumination and endoscope imaging was utilized to gain optical access to the area of interest.