Development of stereoscopic molecular tagging velocimetry

Abstract

 This paper describes the development of a stereoscopic molecular tagging velocimetry (sMTV) technique for measuring the instantaneous three-component velocity field over a plane in a flow. The calibration technique employed allows the stereo imaging parameters to be determined directly from a target image without the direct physical measurement of those parameters. Effects of index of refraction variations are accounted for approximately in the calibration method. Sensitivity analysis and target test experiments for a typical optical setup indicate maximum error levels for the in-plane components to be nominally the same as two-component MTV measurements. The error in the out-of-plane velocity component can be one to three times larger, depending on the stereo viewing angle. Experimental results are presented to validate the sMTV technique against other known measured results, along with an application to the highly three-dimensional flow field near the tip of a model propeller.