Numerical analysis of the wake dynamics of a propeller

This paper investigates the inception mechanism of propeller wake instability based on an improved detached eddy simulation method at a moderate advance coefficient of J = 0.65. Computational fluid dynamics simulations involving a rotating propeller using a dynamic overset technique are performed at J = 0.38 and J = 0.88 to validate the numerical approach, and these results are compared against experimental data of thrust and torque coefficients and phase-averaged axial velocity from the literature. The results indicate that propeller wake instability results from interactions among vortex structures behind the propeller and the high-speed shear layer. In addition, the diffusion of azimuthal velocity plays an important role in the mutual induction process. Finally, we propose a model that includes the main physical processes leading to tip vortex instability and can predict the time and location of vortex pairing. The present study provides deeper insight into the flow physics driving the tip vortex pairing process.