Erosion Control for Highly Efficient Propellers Using a Boundary Element Method Coupled With a Bubble Dynamics Model

A combined approach for controlling the erosion risk of marine propellers is introduced in this paper. By means of a BEM code, the propeller flow in terms of velocity and pressure distribution is simulated. Cavitation bubbles are released at the leading edge of the propeller, and their dynamical behavior is modeled by the Rayleigh-Plesset Equation. These bubbles are interpreted as an idealized form of propeller cavitation, which can highlight unfavorable pressure distributions as well as crucial details in the blade design that could potentially cause erosion. For this purpose, the bubbles are traced when passing the blade surface, and their growth and shrinkage is evaluated. Inspired by the so-called Discrete Bubble Method, the acoustic pressure radiated by a collapsing bubble is related to a potential loss of material, i.e. the erosion risk. The influence of the ship’s wake field can be taken into account by the method, and it turns out that the wake field can have a big influence on the erosion risk. This paper addresses the theoretical framework of the method and reports on its implementation using DTU’s panel code ESPPRO. The newly developed tool is tested for two propeller designs and their respective design variants. Results obtained by the tool are compared to results of well-established DES erosion analysis.