INTERACTION BETWEEN GRAVITY WAVES 

 AND FINITE TURBULENT FLOW FIELDS 



Daniel Savitsky 



Stevens Institute of Teohnology 

 Hoboken, New Jersey 



ABSTRACT 



A laboratory study of the interaction of deep water 

 gravity waves progressing into a turbulent flow field 

 produced by a finite width grid towed In a wide tank 

 showed wave height attenuation of nearly 90% In the 

 grid wake and wave height amplifications of nearly 75% 

 In the still water outside the wake. The transverse 

 gradient of longitudinal flow In the wake was predom- 

 inantly responsible for the large wave deformations 

 and precluded an evaluation of direct turbulence effects. 



A simple, analytical solution using wave refraction, 

 diffraction and superposition concepts Is developed 

 which qualitatively reproduces the measured results. 



I. INTRODUCTION 



As gravity waves progress from their source of origin, they 

 encounter a variety of ocean environments which may Interfere with 

 their ordered motion and, consequently, alter the amplitude and 

 direction of the wave system. Although an extensive literature exists 

 on the mechanism of wave generation and their subsequent propaga- 

 tion through still water or a uniform flow, only recently has some 

 attention been given to waves moving through a non-uniform flow -- 

 ajid these have been restricted to relatively weak velocity gradients 

 normal to the wave direction. 



In a realistic ocean environment, gravity waves may encounter 

 regions of turbulent flow, particularly in the upper layers. These 

 oceanic turbulent flow fields can be developed by various geophysical 

 mechanlsmis. For example, the action of unsteady wind shear stresses 

 exerted against the surface of the sea; the breaking of wave crests 



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