3D planar velocity measurements, using Mach-Zehnder interferometric-filter-basedplanar Doppler velocimetry (MZI-PDV) and imaging fibre bundles

摘要

Three component planar flow-field measurements are made using imaging fibrebundles to port different views of the measurement plane, defined by a laserlight sheet, to a single imaging head. The Doppler frequency shifts of lightscattered by particles entrained in the flow are transduced to intensityvariations using a Mach-Zehnder interferometric filter. The free spectral rangeof the filter can be selected by adjusting the optical path difference of theinterferometer. This allows the velocity measurement range, sensitivity andresolution to be varied. Any laser wavelength may be used. A phase lockingsystem has been designed to stabilise the interferometric filter.