Development of a planar three-component velocimeter using Dopplerglobal velocimetry (DGV) and PIV

摘要

Doppler global velocimetry (DGV) is a planar velocity measurementtechnique, which is based on the determination of the Doppler shift oflaser light scattered off particles by using a molecular filter.Currently a pulsed Doppler global velocimeter is being constructed atthe Institute of Fluid Dynamics. An out-of-plane component of eachvelocity vector in the laser-illuminated plane is obtained by thatconfiguration. The experimental setup is extended so as to measure thein-plane component of those velocity vectors by using particle imagevelocimetry (PIV). Thus, a measurement system is being developed whichis capable of obtaining three components of the velocity vectors locatedin a plane by using one single camera system. A velocimeter based onpulsed DGV consists of a long-pulse laser for the flow illumination, animage acquisition system and the molecular filter cell. Thespecifications of each single component have a major effect on theoverall system performance. Therefore the technical specifications ofall velocimeter components have been evaluated experimentally.Evaluation data are presented in this report. First results ofcalibration measurements are also shown and an outlook on upcoming stepsof the system development is given