Session: 06-14-02 Underwater Vehicles and Design Technology II

Paper Number: 79762

79762 - Influence of Sail Design Parameters on Unsteady Propeller Thrust for Underwater Vehicles 

With the advancement in the detection capability of sonar technologies, the hydro-acoustics of naval vessels have attracted considerable attention to enhance the stealth capability of such vessels. In the range of general cruising speeds, marine propellers radiate considerable hydro-acoustic noise. Specifically, the hydro-acoustic noise, which is also known as the blade rate (BR) noise, pertaining to multiples of the number of propeller blades and rotational speed of the blade, is significant. The BR noise is produced by unsteady thrusts generated by marine propellers which rotate in circumferentially non-uniform wakes of ship hulls. Because submarines and other underwater vehicles deployed for undersea defense systems must perform covert missions, it is necessary to reduce unsteady propeller thrusts to lower the BR noise. In this work, a parametric study was performed on the sail design under unsteady propeller thrusts by Reynolds-averaged Navier–Stokes simulations (RANS) simulations. The RANS simulations were validated for multiple propeller models and wake profiles and used to compute the unsteady propeller thrust of an underwater vehicle. The DARPA SUBOFF submarine with the INSEAN E1619 propeller was adopted as a benchmark. The propeller unsteady thrusts were computed for various axial sail locations and sail widths. Dominant harmonics of the computed propeller thrusts were analyzed via Fourier series. A correlation analysis was performed between the harmonics of the unsteady propeller thrust and inflow wake. The predicted amplitude of the propeller thrust for the aft-fitted sail model was nearly two times that for the original fore-fitted sail model. The dominant harmonic was significantly lowered by altering the sail width. Positive correlation coefficients were obtained at several harmonics that did not match the number of blades. The findings can provide reference for future research and design processes of underwater vehicles.

Presenting Author: Kenshiro Takahashi Naval Systems Research Center, Acquisition, Technology & Logistics Agency

Authors:

Kenshiro Takahashi Naval Systems Research Center, Acquisition, Technology & Logistics Agency
Jun Arai Naval Systems Research Center, Acquisition, Technology & Logistics Agency
Takayuki Mori Naval Systems Research Center, Acquisition, Technology & Logistics Agency