Numerical study of scale effect on the wake dynamics of a propeller

Abstract

In this study, the effects of the scale on the evolution of propeller wake is simulated and analyzed under open water conditions. The simulation is conducted using numerical techniques based on the detached eddy simulation method. The open water performance such as thrust and torque are analyzed for validation, and the instantaneous flow field, vortical structure and the kinetic energy spectra are investigated for the scale effect on the wake dynamics of a propeller. The results indicated that the influence of scale effect on load and wake dynamics of a propeller can differ significantly under different conditions. Under lighter loading condition, the average spanwise circulation at full-scale are considerably larger than those at model-scale at the range of inner radius, and the full-scale propeller exhibits a stronger blade shed vortex. Analysis of vortical structure shows that the transition-to-instability position of vortices vary under different conditions. Power spectral density analysis of the kinetic energy demonstrates that the kinetic energy of full-scale propellers is generally proportionally larger than that of model-scale propellers.