The Naval Postgraduate School has added wave making capability to the existing small tow tank that resides on campus. A new collaborative research effort between the Systems Engineering and Mechanical and Aerospace Engineering Departments is underway that utilizes this new capability. The aim of this new effort is to understand and predict the unsteady hydrodynamic loads experienced by a submerged vehicle operating near the surface. The tow tank was originally built around 1970 but only had the capability of testing models at slow speed in calm water. Even with this limited capability, a number of interesting studies were conducted in the facility including measuring the drag on a towed hydropower turbine and examining the forces due to collisions between floating ice equivalent objects and a composite plate. The new wave making capability in the tow tank is provided by a vertical plunging wedge that was modeled off of the sediment tank wavemaker at the United States Naval Academy. The wedge rides on a pair of vertical rails with the oscillation amplitude and frequency controlled by a linear actuator and electric motor. A variable angle wave absorbing beach is planned for the opposite end of the tank. An additional component of this modernization effort is the creation of a numeric tow tank, using ANSYS CFX, which can simulate the wave dynamics in the tank. This allows complementary numerical and experimental components of future research efforts. The current experimental effort involves characterizing the performance of the wavemaker and quantifying the wave environment throughout the tank. The wedge to wave amplitude transfer function has been determined over the relevant amplitude and frequency space. The uniformity of a wave crest has also been examined. For the numeric tow tank work, the wedge motion has been duplicated and the simulated wave elevation and propagation down the tank are being compared to experimentally measured results.

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