Investigation of Double-Diffusive Convection Using an Ultrasonic Pulse-Echo Technique

Abstract

Propagation of ultrasound is investigated in an aqueous solution stratified by two solutes which diffuse at different rates. Both the finger interface and the diffusive interface are considered. Following correction for background absorption, edge effects, and refraction, attenuation of the order of 1.4 dB/cm is observed in the finger interface, while no attenuation is detected in the diffusive interface. The attenuation increases with frequency from 0.8 to 25 MHz. For higher frequencies, up to 42 MHz, the attenuation is constant. The loss is attributed to an as yet unspecified scattering mechanism.