Wavefront sensing for single view three-component three-dimensional flow velocimetry
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We present the application of wavefront sensing to particle image velocimetry for three-component (3C), three-dimensional (3D) flow measurement from a single view. The technique is based upon measuring the wavefront scattered by a tracer particle and from that wavefront the 3D tracer location can be determined. Hence, from a temporally resolved sequence of 3D particle locations the velocity vector field is obtained. Two approaches to capture the data required to measure the wavefronts are described: multi-planar imaging using a distorted diffraction grating and an anamorphic technique. Both techniques are optically efficient, robust and compatible with coherent and incoherent scattering from flow tracers. The depth (range) resolution and repeatability have been quantified experimentally using a single mode fiber source representing a tracer particle. The anamorphic approach is shown to have the greatest measurement range and hence was selected for the first proof of principle experiments using this technique for 3D particle imaging velocimetry (PIV) on a sparsely seeded gas phase flow.
KeywordsParticle Imaging Velocimetry Particle Image Tracer Particle Diffraction Order Imaging Lens
The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC, UK) for funding under grant reference GR/S61720/01. The work was partially funded by a grant from PPARC under the Smart Optics Faraday Partnership with additional DSTL funding. HIC acknowledges support from EPSRC and UK ATC.
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