Predicting Fluid Cavitation: Improving ship propeller efficiency with realistic simulations

Predicting and reducing fluid cavitation is essential in many industrial applications, including ship propellers. Computational fluid dynamics (CFD) software can be used to predict fluid cavitation and explore alternative designs from early in the design process. This white paper considers important aspects of cavitation simulation for ship propellers. It assesses the relative impact of potential errors on simulation accuracy, how to reduce their impact, and the advantages of simulating full-scale propellers over physical testing of scale models.

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Use CFD simulation to predict fluid cavitation and reduce its impact

Cavitation in fluid mechanics is caused by a sudden reduction in fluid pressure, which allows a phase change to occur and bubbles of gas to form in the liquid. This occurs in many fluid flows, especially in rotating machinery such as pumps, valves, and propellers. Fluid cavitation leads to vibration, noise, and erosion and can cause structural wear and damage. In marine applications propeller cavitation reduces propulsion efficiency and creates erosion on both the hull and propeller blades. It is therefore important to accurately predict if cavitation will occur, where on the propeller it can be found, and ensure propeller designs reduce or prevent fluid cavitation as much as possible.

Multiphase modeling using computational fluid dynamics (CFD) is a vital tool for understanding cavitation. Physical tests of scaled propellers are of limited use, due to the differences between their predictions and real-world, full-scale operating conditions. CFD can accurately predict cavitation and enables fast investigation of multiple designs.

Learn more about the author and his background in marine computational fluid dynamics (CFD)

Professor Milovan Peric has worked on CFD and its applications in marine for over thirty years and has held research positions in both academia and commercial software companies. He is co-author of the popular book “Computational methods for fluid dynamics” and author or co-author of about 200 papers on the development and application of CFD. He currently holds a research position at the Institute of Ship Technology, Ocean Engineering and Transport Systems at the University of Duisburg-Essen, and is a Senior Consultant on marine CFD for Siemens Digital Industries Software.

Learn how to perform accurate cavitation simulation

Cavitation on a ship propeller can be accurately predicted with the common cavitation models available in CFD codes such as Simcenter STAR-CCM+ This paper looks in detail at the challenges you may encounter when running a cavitation simulation. Learn how to assess the impact of:

• Turbulence models
• Grid resolution
• Propeller geometry
• Scale effects

On your cavitation simulation results. The paper includes comparisons between CFD simulations and experimental data from SVA Potsdam GmbH.