Abstract
Optical tomography is applied to the speckle photographic measurement of an asymmetric flow field with variable fluid density. The convolution back projection algorithm is used for obtaining the 3-D density distribution. Noise in the experimental data is reduced by spline smoothing. The method is verified with a steady, laminar, axisymmetric helium jet exhausting vertically into the ambient air, and then applied to a non-axisymmetric helium jet for determining the helium concentration. It is found that speckle photographic recordings are very adequate for tomographic reconstruction, because they provide a high number of data points from each projection. The influence of the limited number of projections on the reconstruction quality is particularly investigated.
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Dedicated to Professor Dr.-Ing. J. Zierep on the occasion of his 60th birthday
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Liu, T.C., Merzkirch, W. & Oberste-Lehn, K. Optical tomography applied to speckle photographic measurement of asymmetric flows with variable density. Experiments in Fluids 7, 157–163 (1988). https://doi.org/10.1007/BF02332980
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DOI: https://doi.org/10.1007/BF02332980