Experimental and numerical studies on the unsteady propeller thrust of underwater vehicles

Experimental and numerical studies on the unsteady propeller thrust of underwater vehicles are presented. An experiment was conducted in a large cavitation tunnel at the Naval Systems Research Center in Tokyo, Japan. A large dynamometer was used to drive the propeller model, and an aft-body model, consisting of a stern-shaped tail and control surfaces, was fixed upstream of the propeller to simulate the wake of an underwater vehicle. The measured unsteady propeller thrusts were analyzed via a fast Fourier transform, and significant amplitudes were obtained at the blade-rate frequencies. The unsteady propeller thrusts were also examined using computational fluid dynamics under the experimental conditions. The numerical results agreed well with those of the experiment and provided insight into the propeller-thrust fluctuations in the wake.