The primary research topic for this proposal is on cavitation physics and its modelling. Cavitation forms the main constraint in the design of marine propulsion systems in terms of performance, maintenance, and environmental impact. It can cause severe material damage on propellers and rudders, and it is the major source for noise pollution into our oceans; these hindrances offset possible performance gains in efficiency and thus adds to pollution to air. Cavitation is a challenging computational problem, involving turbulent multiphase flow and phase transition over a large span of scales, from sub-millimeter bubbles to ships of 100 m in length or more. We work with analysis and modelling of cavitation in a range of situations, from fundamental understanding of vapour bubble dynamics in turbulent flows to design and performance analysis for real ship applications. In one end of this spectrum, the objectives are to improve our capabilities in simulating cavitation and describing the mechanisms governing the hindrances in question, and on the other end to be able to assess the performance of a complete ship operating in cavitating conditions. More specifically, the main activities for the upcoming year related to the computational resources requested through this proposal are: - DNS simulations of vapour bubble clouds in flows characterised by shear and vorticity. This research is performed within a project funded by the Swedish Research Council (VR 2024-04704). The objective is to improve the description of the bubble dynamics to feed into further model development. - Hydroacoustic characterisation of sound emitted from cavitation through highly resolved compressible simulations of the flow around a sphere and an isolated propeller. The objective is to generate reference data on the acoustic emissions by directly and accurately resolve the sound sources from cavitation and their propagation. - Study the use of scale resolving simulations in ship hydrodynamics and how flow dynamics affect the character of noise emissions from ships. Current state of the art for ship hydroacoustics is still to use RANS, while we here will account for the dynamics of the turbulent ship wake and how that affects cavitation dynamics and the generated noise sources.