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Temporal evolution of the crest region of a deep-water progressive plunging breaker that is propagating left to right with a center frequency of 1.4 Hz (Perlin and co-workers, 1996). |
The experimental hydrodynamics research in the department consists of both laboratory experiments at model scale and field experiments at full scale.
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Temporal evolution of the crest region of a deep-water progressive plunging breaker that is propagating left to right with a center frequency of 1.4 Hz (Perlin and co-workers, 1996). |
The Marine Hydrodynamics Laboratory presently has four major world-class facilities: a wind-gravity-wave interaction flume; a turbulence-free surface interaction recirculating water channel; a capillary-gravity fluid-interaction laboratory; and the 110 m, ship hydrodynamics towing tank.
Experimental techniques employed and further developed include particle-image velocimetry, three-component laser-Doppler velocimetry, high-speed video/photography, and laser-sheet surface detection. Recent laboratory experiments have investigated the complex interactions that occur in fluid dynamics including tri-junction flow at the intersection region of two fluids and a solid; turbulence-wave interactions and associated electromagnetic backscatter signatures; standing and progressive surface wave nonlinearities and interactions; breaking wave processes; dissipation, and regeneration; evolution of near-free surface jets and wakes; incipient instabilities of air-sea interactions; and flow field interactions/dynamics with marine vehicles.
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(a) Pseudo-phase diagram (0.1 sec delay) and (b) amplitude spectrum for the elevation signal from a wave probe at tank center. Steep, nonbreaking, standing wave. Frequency is 1.60 Hz; forcing is 4.15 mm. The same for (c) and (d) except that period-tripled breaking occurs with forcing at 4.57 mm (Perlin and co-workers, 1997). |
Recent experimental work in the towing tank has included IACC yacht seakeeping tests for America's Cup syndicates PACT93 and PACT95, and high-speed planing boat tests in calm water and in waves for General Dynamics Corporation. Appendage variations using a radio-controlled model boat were done in Lake Michigan near Muskegon with the help of several undergraduate and graduate students for Allied-Signal, Inc.
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Shadowgraph image of waves generated by a submerged turbulent jet (Walker et al., 1995). |
In the past five years, the types of vessels tested in the towing tank include SWATH (Small Waterplane Area Twin Hull) ships, catamarans, notched barges, planing boats, and crew boats. A long-term study on the nonlinear motions of a naval cruiser was done to investigate sectional forces and relative wave heights as well as the rigid body seakeeping motions. A very high- speed, unmanned carriage is being designed to increase the ability to do more planing boat work, and to do full-scale submersible testing.
In addition to laboratory-scale hydrodynamic investigations, the department is also very active in full-scale studies. In many applications, it is highly desirable to conduct hydrodynamic experimentation at full scale and in the natural environment. The marine environment is severe, harsh, and often unforgiving. This combination of attri-butes provides an ideal setting for the most real-istic testing possible. The experimental hydrodynamics group is involved in several areas of full-scale experimentation in both the open ocean and in the Great Lakes. Facilities and equipment of the Marine Hydrodynamics Laboratory, the Ocean Engineering Laboratory, the remote sensing group, and the coastal hydrodynamics group all contribute to the full-scale hydrodynamics research.
FACULTY: Beck, Lyzenga, Meadows, Perlin, Sirviente, Troesch, Walker
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A modified hydroplane designed and constructed by students as an independent study project under the guidance of Professor Troesch and Dr. Cohen. It is shown here during sea trials. |
FACULTY: Beck, Lyzenga, Meadows, Perlin, Sirviente, Troesch, Walker