Author

Noriaki Okita

Date of Award

8-1997

Degree Name

Master of Science in Engineering

Department

Mechanical and Aerospace Engineering

Department

Mechanical and Aeronautical Engineering

First Advisor

Dr. Christopher Cho

Second Advisor

Dr. Parviz Merati

Third Advisor

Dr. Iskender Sahin

Access Setting

Masters Thesis-Open Access

Abstract

Two-dimensional, steady-state and time-dependent analysis of wave making phenomenon due to a moving pressure distribution in sub-critical Froude number was performed. The domain is consisted of undisturbed free-surface at y=0, flat bottom at y=-h, and it is unbounded in horizontal direction. The pressure distribution was treated as an ideal model of an air-cushioned-vehicle (ACV). Ideal flow theory and linearized boundary conditions were used. Numerical integration algorithm was developed to evaluate the analytical solution. The surface elevation, bottom pressure profiles, and wave resistance were analyzed as functions of speed and depth.

The steady-state wave resistance calculated from the surface elevation profile resulted in good agreement with reference values, thus the surface profiles under the disturbance as well as downstream of disturbance was verified within the limit of linear theory. Decay of the surface profile was found to be due to the dispersive nature of the water wave. Toe time history of wave resistance was found to be oscillating function about the steady state value, and its frequency depends on the speed. The results of time dependent profiles show progressive wave in upstream of the pressure distribution.

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