Mitigating Cavitation Damage with Micro-Structured Surfaces

• Applicant: Professor Dr. Claus-Dieter Ohl
• Subject Area: Fluid Mechanics ; Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 580228313

This joint proposal by Prof. Claus-Dieter Ohl (Otto von Guericke University Magdeburg) and Prof. Rok Petkovšek (University of Ljubljana) aims to establish a new fluid-mechanical route to mitigate cavitation erosion through micro-structured surfaces (MSS). Cavitation—rapid vapor bubble growth and collapse in liquids—remains a critical problem in hydraulic machinery, as the collapse near solid boundaries cause severe material damage. Building on recent discoveries showing that shock-wave self-focusing during toroidal bubble collapse is the dominant erosion mechanism, the project seeks to engineer surface topographies that deliberately disturb this focusing process and thereby suppress material erosion. The consortium combines expertise in laser microfabrication, high-speed optical diagnostics, and cavitation physics. Three central objectives define the project: (1) develop femtosecond-laser-based surface modification of metals to create defined MSS geometries; (2) elucidate the collapse dynamics of single cavitation bubbles interacting with these MSS using advanced imaging, pressure diagnostics, and coupled fluid–solid simulations; and (3) apply and test the optimized MSS under acoustic and hydrodynamic cavitation conditions to demonstrate erosion mitigation. The work program comprises four tightly linked work packages. WP0 (Ljubljana) develops and fabricates MSS on metals using a novel 2.5 D laser-structuring approach capable of sub-micron precision. WP1 (Magdeburg and Ljubljana) investigates single-bubble collapse near MSS through multi-frame velocimetry, GHz-bandwidth fiber-optic hydrophones, and fluid-structure-interaction simulations in both axisymmetric and 3D configurations. WP2 establishes a hydrodynamic cavitation flow rig at Magdeburg, enabling controlled studies of cavitation inception, bubble collapse, and erosion on MSS in shear flows. WP3 (Ljubljana) examines acoustic cavitation seeded by picosecond laser pulses, progressing from single-bubble to cluster dynamics. The project’s novelty lies in addressing cavitation damage not by material hardening, but through flow- and geometry-based control of bubble dynamics. Preliminary experiments show up to 100-fold reduction in eroded volume when bubbles collapse on structured versus flat surfaces, underscoring the promise of this approach. The research will further clarify how micro-topographies modify toroidal collapse, shock-wave focusing, and erosion, providing design principles for cavitation-resistant surfaces applicable to metals. Comprehensive risk management, FAIR-compliant data handling, and equal-opportunity recruitment are integrated into the plan. The anticipated outcomes include four high-impact publications, open-source simulation tools, and openly shared experimental datasets. The project will pioneer a fundamentally new strategy for cavitation-erosion mitigation through the interplay of surface engineering, bubble dynamics, and high-resolution diagnostics.

• DFG Programme: Research Grants
• International Connection: Slovenia
• Partner Organisation: Slovenian Research and Innovation Agency (ARIS)
• Cooperation Partner: Professor Dr. Rok Petkovsek