A bio-inspired W-shaped trailing edge for suppressing flow-induced noise in an electric water pump for electric vehicles under the rated operating condition: a vortex-sound interaction study

This study focuses on mitigating flow-induced noise in electric water pumps, which has become an increasingly important issue for the acoustic comfort of electric vehicles. Inspired by the noise-reduction function of owl-wing trailing-edge features, a W-shaped trailing-edge configuration is proposed for the pump impeller. By combining a one-way coupled CFD-FEM framework and experimental measurements, this study investigates how trailing-edge geometry influences both the characteristics of acoustic sources and the resulting far-field radiation. A baseline impeller and five redesigned impellers with different cutting depths are investigated, and the numerical predictions are validated experimentally. The results demonstrate that, under the rated operating condition, Design III provides the best hydraulic-acoustic compromise within the tested parameter range. Compared with the baseline impeller, it reduces the overall sound pressure level by 2.6 dB and increases hydraulic efficiency by 2.40 percentage points, while largely preserving the pump head. Spectral and spatial analyses further show that the W-shaped trailing edge effectively weakens the dominant discrete noise components and modifies the distribution of major acoustic sources near the volute tongue. The noise-reduction mechanism is governed by a dual pathway: the enhanced dissipation of wake energy that fundamentally weakens the dipole source strength, and the fragmentation of large-scale coherent vortical structures that reduces the acoustic radiation efficiency. These findings demonstrate that the W-shaped trailing edge is an effective passive control strategy for suppressing flow-induced noise in electric water pumps and provide useful guidance for the low-noise design of rotating fluid machinery.