Atmospheric refraction and propagation over curved surfaces

This thesis presents theoretical and experimental investigations of atmospheric refraction and diffraction of sound over curved surfaces. The main contributions of this work are as follows: The development of an alternative method for calculating the influence of wind on sound propagation in the pre...

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Bibliographic Details
Main Author: Wang, Qiang
Published: Open University 1998
Subjects:
534
Online Access:http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363971
Description
Summary:This thesis presents theoretical and experimental investigations of atmospheric refraction and diffraction of sound over curved surfaces. The main contributions of this work are as follows: The development of an alternative method for calculating the influence of wind on sound propagation in the presence of a ground of finite impedance. The development of numerical models to calculate sound propagation due to monopole and dipole sources over cylindrical or spherical convex and concave surfaces of finite impedance. Laboratory measurements of sound propagation over curved surfaces and comparisons with the proposed theoretical and numerical models. The exploration of the theory for surface wave contributions in an upward refracting atmosphere in the light of obtained experimental data and observation of the surface waves above a convex surface. Experimental and theoretical investigations of the effectiveness of a barrier in the presence of sound speed gradients.