Numerical assessment of erosion risk for composite hydrofoils by the potential energy theoretical method

This study employs a fluid-structure interaction (FSI) framework coupled with an energy cascade-based potential energy erosion metric (E) to numerically assess cavitation erosion risk on composite hydrofoils with varying ply angles ([+45°], [0°], [-45°]). The erosion indicator E is defined as the average of instantaneous pressure-wave power densities exceeding a specified threshold, derived from the time-averaged pressure field and vapor-fraction transport, while the contraction-phase metric α_c characterizes the vapor-fraction reduction rate. Results reveal that bending-twisting coupling effect significantly alters cavitation dynamics and erosion distribution. The bend-twist coupling induced by the +45° ply angle (K = +70) increases the effective angle of attack, producing larger cavitation structures and consequently the highest erosion intensity concentrated in the mid-chord region. Conversely, the −45° bend-twist coupling (K = −70) reduces cavitation scale and shifts the erosion risk toward the trailing edge, while the 0° configuration (K = 0) exhibits intermediate behavior. Crucially, erosion is primarily driven by collapsing large-scale shedding clouds and small closure clouds, with peak risk occurring during attached cavity growth and large cloud shedding/collapse. This work establishes a predictive framework linking composite bending-twisting coupling effect to cavitation erosion mechanisms, providing critical insights for designing erosion-resistant marine composites.