Liquid jet impingement on solid surfaces and liquid pools: Cleaning performance, erosion mechanisms and emerging acoustic insights — A critical review

This review consolidates experimental, numerical and theoretical studies on liquid jets impinging on solid surfaces and liquid pools, linking three intertwined outcomes — cleaning efficiency, material erosion and acoustic emission — to the underlying jet-flow physics. Empirical studies show that nozzle diameter, jet pressure, flow rate, and stand-off distance jointly influence the wall-shear and impact-stress fields that govern soil or deposit removal. These relationships have enabled semi-empirical correlations for cleaned radius across a broad range of Reynolds numbers. High-speed imaging and numerical studies describe the transition from coherent jets to Rayleigh, wind-induced and atomization regimes as inertial and aerodynamic effects increase, while splashing and momentum loss become important once breakup occurs before impact. On impact, erosion is controlled by the pre-impact jet state and the dominant loading pathway, including repeated droplet impact, water-hammer pressure, particle cutting, cavitation collapse and frequency-dependent pressure pulses. Reported erosion rates can scale steeply with impact velocity. For example, aluminum droplet-erosion data show an erosion rate approximately proportional to U 7 . However, this scaling is not universal. It depends on droplet or particle size, impact angle, surface roughness, liquid-film thickness, damage stage, and material response. Acoustic studies show that impact, breakup, cavity collapse, bubble oscillation, and splashing can generate identifiable spectral features from low frequencies to the kHz and tens-of-kHz range. These findings highlight acoustics as a promising, but still configuration-dependent, non-intrusive diagnostic. By collating correlations for cleaned radius, breakup length, droplet size, splash ratio, erosion rate and acoustic response, this review identifies the regime-specific limits of current models. It also highlights major gaps, especially the lack of simultaneous flow–sound–erosion measurements under extreme, non-Newtonian, particle-laden, chemically active and metallic-jet conditions. The review therefore outlines a roadmap for designing quieter, more efficient and less damaging liquid-jet systems for cleaning, machining and erosion-testing applications.