title: Intensity fluctuations of ultrasonic scattering in a highly turbulent flow.
abstract: Aspects of ultrasound intensity fluctuations backscattered from additive microstructures in a turbulent flow have been investigated theoretically and experimentally for the conditions of a small insonified volume, a high sound frequency and strong turbulence. These conditions are typically found in high resolution Doppler sonar applications. An easily applicable expression for the auto-correlation of scattering intensity fluctuations is obtained by introducing open-channel turbulence theory, a semi-empirical scalar spectrum (including a Batchelor spectrum) and a Gaussian window function. Experiments carried out in a laboratory-clear water, open-channel flow for different turbulence levels verify the underlying assumptions. A good agreement is found with the predictions made with the above-derived expression. The feasibility of extracting flow information from the backscattered intensity fluctuations is discussed.
authors.affiliation: Laboratoire de Recherches Hydrauliques, Ecole Polytechnique Fédérale Lausanne, Switzerland. cshen@ade.com
authors.forename: C
authors.initials: C
authors.lastname: Shen
authors.forename: U
authors.initials: U
authors.lastname: Lemmin
mesh_terms: D000162:Acoustics; D014465:Ultrasonics