NUMERICAL ANALYSIS ON MODEL- AND FULL-SCALE UNSTEADY PROPELLER FORCE FOR UNDERWATER VEHICLE

Submarines and other underwater vehicles must meet extensive specifications regarding their acoustic signatures to perform covert missions. However, marine propellers produce unsteady forces, resulting in undesirable noise. In this context, the unsteady propeller force of an underwater vehicle was analyzed at the model scale and full scale, based on computational fluid dynamics. The DARPA SUBOFF submarine and INSEAN E1619 propeller were adopted as benchmark models. The propeller rotational speeds under self-propelled conditions were determined using the body-force propeller method. The dominant harmonics of the unsteady propeller forces were analyzed using the Fourier series. The effects of pre-swirl flow generated by the helmed stern planes were investigated. Reynolds scaling was examined to predict the amplitudes of the propeller forces at full scale, based on the model-scale values.