Zhou, J.; Sun, P., and Pan, L., 2022. Modal analysis of the wake instabilities of a propeller operating in coastal environments. Journal of Coastal Research, 38(6), 1163–1171. Coconut Creek (Florida), ISSN 0749-0208.
The dynamic characteristics of propeller wakes are a function of hydrodynamics, noise propagation, and structural vibration, among other factors. The evolution of propeller wake flow mechanisms from the near field to the far field has always been a significant topic of turbulence research. Numerical simulations of propeller wakes under different loading conditions were conducted using the improved delayed-detached eddy simulation (IDDES) method. Based on the mode decomposition technique, the results of numerical simulations were used as the input data to perform a reduced-order analysis of propeller wake fields. The results showed that there is a considerable difference between the morphology characteristics of propeller wakes under high and low loading conditions, where the former tends to be unstable earlier in the evolution. According to the mode decomposition results, with decreasing mode frequency, there is strong circumferential diffusion in the tip vortices, which is more pronounced under the high loading condition and at locations further downstream. Circumferential diffusion is a key factor triggering the propeller wake to change from the stable to the unstable state. The present work can provide a significant reference for the design and optimization of next-generation marine propellers operating behind vessels sailing in both coastal and offshore environments.