Cavitation Erosion: Model to Full Scale

Understanding cavitation erosion employing the U.S. Navy’s Large Cavitation Channel

Cavitation-induced erosion of naval propulsors, control devices, and surfaces is a critical consideration due to its effects of performance loss and surface damage, which lead to costly repairs or part replacement. An example is the redesign of the rudders of the USS Arleigh Burke to avoid the effects and associated repair costs of cavitation erosion. The damage is caused by the accumulative effects of the near-wall collapse of cavitation bubbles.  Cavitation bubbles are water vapor bubbles that form under low pressure conditions that impact highly focused energy on a marine surface.  The repeated impact on the surface erodes substantial material and degrades the hydrodynamic and structural performance. Difficulty in predicting cavitation erosion comes from inadequate understanding of cavitation erosion mechanisms including a knowledge gap in reliable size-scaling laws and uncertainty in interpreting model scale measurements to the full scale of a naval vessel.

The overall goal of the project is to improve the Navy’s understanding of cavitation erosion and associated performance loss of naval propulsors, control devices, and surfaces, as well as establish the capabilities in the William B. Morgan Large Cavitation Channel (LCC) to undertake full-scale experiments of cavitation erosion. The LCC is a large variable-pressure closed-loop water tunnel that has been operated by the U.S. Navy on President’s Island in Memphis, TN, since 1991. The LCC is one of the world's largest and most technically advanced high-speed, variable-pressure water tunnel facilities. It is capable of testing all types of ship and submarine propellers and propeller-hull interactions with model scales sufficiently large to match the largest towing and turning basins in the world. Its design permits the measurement of submarine and surface ship power, efficiency and propeller noise by using models in a controlled but realistic environment.

The objectives of this project are the following: (1) Conduct experimental cavitation erosion studies from the model to the full scale, as well as high-fidelity numerical simulations to better understand, predict, and address cavitation erosion. The team will employ facilities with controlled conditions that range in size from the model scale with a test section of less than one square inch to approximately full scale with a test cross section of approximately 100 square feet using the LCC. (2) Perform correlation studies using experimental measurements and high-fidelity simulations provide scaling laws and develop simulation tools to capture cavitation regimes. (3) Develop scaling relations of cavitation erosion statistics as a function of material properties and flow conditions in non-dimensional parametric space and develop functional relations between cavitation erosion rate for different test methods. Outcomes of this project can be used to improve U.S. Navy vessel design as well as improve shipbuilding to address cavitation erosion. 

The project is a large collaborative effort between the University of Memphis, University of Michigan, and the Naval Surface Warfare Center Carderock Division under the sponsorship of the Office of Naval Research. Dr. Daniel Foti is the overall principal investigator with Dr. Amir Hadadzadeh and Dr. Yuan Gao, all in the Department of Mechanical Engineering, funded on the project.  

For more information on this project, contact Foti at dvfoti@memphis.edu.