EFFECTIVE PARAMETER INVESTIGATION IN NUMERICAL SIMULATION OF CAVITATION AND NON-CAVITATION FLOW AROUND A DTMB 4119 STANDARD PROPELLER

In this paper, cavitation and non-cavitation ows around a marine propeller, DTMB 4119, with the RANS method, the K- 03b5 turbulence model, the Singhal transfer model and the mixed model, were solved. The velocity and pressure elds around the propeller surfaces were obtained using the equations of continuity, momentum and the K-03b5 model of turbulence. The pressure coe- cient for two sections of the propeller with experimental data (Jessup 1989) in non-cavitation ow, and three sections in cavitation ow with numerical data (Sun 2008), was validated. Thrust, torque and eciency coecients were extracted for this propeller in eight simulations and compared with experimental data. The cavitation pattern was specied and also the position and the cavity development area were obtained. Furthermore, numerical investigations for the three important parameters, such as: advance coecient, propeller working depth and surface roughness of propeller in cavitation ow, were undertaken. An advanced coecient eect study on the propeller surfaces showed that with less advance coecient, more vapor phase value is observed. Also, cavity boundaries are extended. Between advance coef- cient values of 0.833 and 0.7, cavity volume results are less than the advance coecient values of 0.7 and 0.6. So, the cavity boundaries are signicantly extended. By downing the propeller working depth under open water conditions (increasing hydrostatic pressure), cavity boundary movement, cavity volume variation and curve peak reduction of the vapor phase volume fraction were investigated. The cavity center was away from the leading edge and the probability of tip vortex cavitation was reduced. The sustainability of tip vortex cavitation is more than sheet cavitation, the casue of which is, rst, tip vortex cavitation, and then, sheet cavitation of the leading edge. Investigation on propeller surface roughness showed that optimal roughness height could be found. A and B models showed less cavity volume than the smooth model, while the C model showed more cavity volume. When roughness height was increased, the vapor phase volume fraction was rstly reduced, the results of A and B models being nearly the same. As a result, increasing the roughness height to a specic value caused a decrease in the vapor phase volume fraction value, which afterwards grew.