title: Frequency and wavelength prediction of ultrasonic induced liquid surface waves.
abstract: A theoretical investigation of parametric excitation of liquid free surface by a high frequency sound wave is preformed, using potential flow theory. Pressure and velocity distributions, resembling the sound wave, are applied to the free surface of the liquid. It is found that for impinging wave two distinct capillary frequencies will be excited: One of them is the same as the frequency of the sound wave, and the other is equal to the natural frequency corresponding to a wavenumber equal to the horizontal wavenumber of the sound wave. When the wave propagates in vertical direction, mathematical formulation leads to an equation, which has resonance frequency equal to half of the excitation frequency. This can explain an important contradiction between the frequency and the wavelength of capillary waves in the two cases of normal and inclined interaction of the sound wave and the free surface of the liquid.
authors: Parallel Processing Laboratory, Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Ave, Tehran 15875-4413, Iran.
authors: Ehsan
authors: E
authors: Mahravan
authors: Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Ave, Tehran 15875-4413, Iran. Electronic address: hnaderan@aut.ac.ir.
authors: Hamid
authors: H
authors: Naderan
authors: Department of Mechanical Engineering, Amirkabir University of Technology, 424 Hafez Ave, Tehran 15875-4413, Iran.
authors: Ebrahim
authors: E
authors: Damangir
keywords: Capillary waves; Free surface; Potential flow; Sound wave; Ultrasound