Cavitation
General information
Cavitation is the transition of liquid water to vapour in low pressure areas. Cavitation develops spontaneously when the local pressure in a fluid drops below the saturated vapour pressure of water. This phenomenon is in fact the boiling of water at room temperature, not by heat but by reducing the pressure. Cavitation bubbles of varying size collapse fiercely when entering a area of higher pressure. The collapse of the cavitation bubbles causes high-pressure shockwaves in the fluid. Periodic fluctuations of the pressure field as caused by the dynamics of the cavitation on the rotating propeller blades excite the ship hull, a feature which can cause vibration and noise. Under certain conditions cavitation can also cause material erosion.

Services & Activities
The Propulsors and Cavitation Knowledge Team of MARIN offers its expertise on a wide range of cavitation related topics. Most common are the evaluation of propeller designs on cavitation related pressure fluctuations to prevent ship vibration problems and the assessment of the risk of cavitation erosion.

In its history MARIN has tested a vast number of propellers now contained in its stock of models. For ships such as ferries and cruise liners for which comfort aspects are essential MARIN assists their customers in meeting strict design requirements of today. For naval applications MARIN offers their experience in designing low-noise propellers. These propellers have a delayed inception of cavitation as caviation is a primary noise source. For propellers of merchant ships a compromise between the propulsive efficiency and cavitation hinderance is aimed for from the early start of the design. Verification of the cavitation performance by model experiments is often requested by ship owners.

Facilities & Tools
Cavitation investigations are carried out in the following MARIN facilities:

  • Depressurised Wave Basin: Cavitation observation and measurements of the pressure fluctuations on the hull above the cavitating propellers at a ship model
  • Cavitation Tunnel (CT): Cavitation research involving dedicated test set-ups that are not feasible in the DTT.
For cavitation related issues a large number of experience based tools and CFD programs (such as ReFRESCO, which developments started to enable the calculation of cavitation in viscous-flows) are available.
The main tools used are:

Software Sales
Some software tools are available for commercial use outside MARIN. A complete overview of these software tools for sale can be found under Software Sales.

Experience
The list below gives a review of cavitations projects carried out at MARIN:

  • GRIP 2014
  • TIPVOR (RNN/US) 1996-2000
  • AFDEASR 1990
The following Joint Industry Projects (JIPs) were focussed on cavitation:

  • CoCa (2000-2003)
Full scale cavitation observations are indispensable as feedback for propeller design and interpretation of model tests. MARIN offers a unique full scale consulting and monitoring service, and has gained considerable experience in a broad field of ship types over the years Leaflet (PDF) .

Most recent cavitation related papers presented by MARIN
(complete overview of papers can be found under Publications)

Influence of grid setup on the prediction of hydrofoil cavitation
Negrato, C., Lloyd, T., Terwisga, T.J.C. van, and Bensow, R., 19th Numerical Towing Tank Symposium (NuTTS), St. Pierre d'Oléron, France, 2016

Towards cavitation modelling accounting for transition effects
Reverberi, A., Lloyd, T. and Vaz, G., 19th Numerical Towing Tank Symposium (NuTTS), St. Pierre d'Oléron, France, 2016

Comparison of uRANS and BEM-BEM for propeller pressure pulse prediction: E779A propeller in a cavitation tunnel
Perali, P., Lloyd, T. and Vaz, G., 19th Numerical Towing Tank Symposium (NuTTS), St. Pierre d'Oléron, France, 2016

Finite Mass Transfer Effects in Cavitation Modelling
Schenke, S. and Terwisga, T.J.C. van, 19th Numerical Towing Tank Symposium (NuTTS), St. Pierre d'Oléron, France, 2016

Validation of computational and experimental prediction methods for the underwater radiated noise of a small research vessel
Frans Hendrik Lafeber and Johan Bosschers, 13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark, 2016

Most recent cavitation related articles written for MARIN Report:
(complete overview of articles can be found under Publications)

Observing cavitation for naval applications
Ingo Drummen, MARIN Report, 2017

Accurate predictions for noise levels of cavitating propellers now possible
Frans Hendrik Lafeber, Johan Bosschers & Yvonne Koldenhof, MARIN Report, 2016

Success of renowned ‘Wageningen B’ followed by the future-ready C & D-Series
MARIN Report, 2015

From fresh Breathe to hot Savannah
Enrico Della Valentina, MARIN Report, 2015

ReFRESCO, a CFD code tailored to the maritime world takes shape
Guilherme Vaz & Hoyte Raven, MARIN Report, 2015

Contact
For more information on how MARIN can help your organisation with the issue of cavitation, please contact the Propulsors and Cavitation Knowledge Team at: propulsors@marin.nl

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