Design of an internal wave generator for experimental applications

Abstract

This thesis presents the design of an internal wave generator for experimental applications. It is based on the previous design by Gostiaux, Didelle, Mercier and Dauxois, however it is constructed on a smaller scale to be of use in one of the smaller tanks in the Nonlinear Dynamics Lab at MIT. The generator operates by forming a traveling sinusoidal boundary that results in a single internal wave beam propagating through the fluid medium. The boundary is created by stacking 12 plates on top of each other, and using a rotating camshaft to drive them in a sinusoidal fashion. Measurements of the oscillation of each plate shows that the motion induced in each plates by the camshaft is very close to sinusoidal, and that the generator can successfully produce oscillations of amplitudes as low as 3 or 4mm. Schlieren images show that the generator is capable of producing a single wave beam, with minimal disturbances in other directions. In addition, the direction of the wave beam can be controlled by the speed of rotation of the camshaft, and wave beams of different widths can be produced by altering the camshaft design.