Reconstructing Three-Dimensional Fluid Velocity Vector Fields from Acoustic Transmission Measurements
A theory with supporting experimental evidence is presented for reconstructing the three-dimensional fluid velocity vector field in a moving medium from a set of measurements of the acoustic propagation time between a multiplicity of transmitter and receiver locations on a stationary boundary surface. The inversion of the integrals’relating the acoustic propagation path to the propagation time measurements is affected by linearization and discrete approximation of the integrals and application of an algebraic reconstruction technique (ART). The problem of the presence of certain invisible fluid flow functions is treated. Since this technique does not require the presence of scattering centers or the optical transparency of the medium, it may be applied in many cases (i.e., turbid, opaque, or chemically pure media) where Doppler or optical (e.g., laser holography) methods fail.
KeywordsDoppler Method Algebraic Reconstruction Technique Laboratory Coordinate System Fluid Vortex Laser Holography
Unable to display preview. Download preview PDF.
- 1.Johnson, S. A., J. F. Greenleaf, W. F. Samayoa, F. A. Duck, and J. Sjostrand: Reconstruction of three-dimensional velocity fields and other parameters by acoustic ray tracing. 1975 Ultrasonics Symposium Proceedings, IEEE Cat. #75 CH0 994–4SU.Google Scholar
- 2.Johnson, S. A., J. F. Greenleaf, A. Chu, J. Sjostra.nd, B. K. Gilbert, and E. H. Wood: Reconstruction of material characteristics from highly refraction distorted projections by ray tracing. Image Processing for 2-D and 3-D Reconstruction from Projections: Theory and Practice in Medicine and the Physical Sciences. A Digest of technical Papers, August 4–7, 1975, Stanford, Calif.ornìa, pp TUB 2–1 - TUB 2–4.Google Scholar
- 3.White, R. W,: Acoustic ray tracing in moving inhernogeneous fluids. Journal, Acoustical Society of America, Vol,. 53, No. 6, 1973.Google Scholar
- 5.Greenleaf, J. F., S. A. Johnson, W. F. Samayoa, and C. R. Hansen: Refractive index by reconstruction: use to improve compound B-scan resolution. (See this Proceedings, 1976 ).Google Scholar
- 6.Data shown in Figure 7, top left panel, is an image of the difference between the time of flight with flow and without flow (fast arrival = white, no change = gray, slow = black) vs scan position (left to right) Vs angle of view (top to bottom).Google Scholar
- 7.Johnson, S. A.: Patent pending.Google Scholar