ASA 124th Meeting New Orleans 1992 October

3pUW3. Use of vector Bragg wave-number scattering condition in bistatic scattering experiments.

John Oeschger

Univ. of Rhode Island, Kingston, RI

Louis Goodman

Diane Szargowicz

Naval Undersea Warfare Ctr., Newport, RI

Peter Hebda

Americom Corp., Middletown, RI

Applying the Born approximation to a buoyant plume yields the Bragg scattering condition that determines along with knowledge of the scattering potential, the scattered wave at any given scattering angle. The Bragg scattering condition allows for information obtained from the same Bragg direction albeit different scattering angles to be pieced together to form an entire Bragg wave-number spectrum of the scatterer. Data are taken in a multiple bistatic configuration whose geometry is predetermined via knowledge of the bandwidth of the transducers and the desired overlap of the resulting Bragg phase space. Results are given for a buoyant axisymmetric laminar plume. As an aside of the Bragg scattering condition an empirical formula derived from the far-field expressions for the Green's function solution to the Hemholtz equation given the scattering dimensionality of the plume, which is acoustically measured and shown to give expected results.