RECONSTRUCTING THREE-DIMENSIONAL TEMPERATURE AND 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 and temperature field in a moving medium from a set of measurements of the acoustic propagation time between multiple 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 obtained by linearization and discrete approximation of the integrals and application of an algebraic reconstruction technique (ART). The inversion of these integrals provides reconstructions of both acoustic refractive index and vector fluid velocity. Since this technique does not require either 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.