Session: 13-03-05: General: Mechanics of Solids, Structures and Fluids V

Paper Number: 173324

First Near-Ship-Scale Cavitation Erosion Study: Material Response and Scaling Effects 

        Cavitation erosion has posed a persistent challenge for naval engineering for over 130 years. It is a complex damage mechanism wherein cavitating bubbles implode near a material surface, causing localized damage. Given the extremely high bubble count and rapid collapse dynamics, quantifying the damage from individual bubble events is impractical. Consequently, standardized laboratory methods, such as ASTM G134 and G32, have been developed to estimate cavitation damage. These techniques employ either a cavitating jet or a vibratory apparatus and are favored due to the logistical and financial challenges of conducting full-scale cavitation erosion experiments. However, these lab-scale tests are not suitable for a comprehensive understanding of the full-scale cavitation erosion phenomenon. As such, the current study aims to present the results of a near-ship-scale cavitation erosion experiment. 

        This test is the first of its kind, as the William B. Morgan Large Cavitation Channel (LCC) in Memphis, TN, a facility capable of reaching flow speeds up to 35 knots (40 mph), controlling dissolved air contents in water, and replicating ship-scale cavitation environments, was utilized. A hydrofoil measuring 2.134 m (7.0 ft) in length and 3.048 m (10.0 ft) in width was mounted at a -2° angle of attack to generate cavitation. The resulting sheet cavitation covered 50% of the hydrofoil chord. To investigate spatial variation in damage, four rows of test samples were placed along the hydrofoil in the streamwise direction: two rows upstream of cavity closure (Rows A and B) and two downstream (Rows C and D). 

        Three materials commonly used in cavitation erosion studies, Aluminum 1100, Nickel 200, and Copper 110, were tested inside the cavitation tunnel. The test coupons, measuring 28 cm × 10 cm × 1.2 cm, were analyzed post-exposure using a Keyence VR-6000 profilometer to characterize damage. This study aims to establish quantitative relationships between material properties and cavitation erosion behavior. 

        Initial findings reveal significant differences between laboratory-scale (ASTM G134) and full-scale (LCC) results. Notably, the cumulative pitting rate measured under ASTM G134 conditions is approximately two to three orders of magnitude higher than that observed in the LCC. Furthermore, damage in the LCC tests exhibited strong spatial dependence due to non-uniform cavitation intensity, particularly downstream of the cavity closure (Row C), where the highest levels of pitting and deformation were consistently observed. In contrast, ASTM G134 samples, circular with diameters of 12 millimeters, do not capture such spatial variation. 

        This presentation aims to answer two questions. First is looking at how the scaling from ASTM G134 to the large cavitation tunnels affects the pitting behavior of the material. Second is looking for the quantitative correlation between the LCC tested material pitting damage and the material properties. This study will pave the pathway towards a comprehensive understanding of the material properties-cavitation erosion-cavitation scale relationship.  

 

Acknowledgement 

The authors would like to acknowledge the financial support provided by the US Office of Naval Research (ONR) Code 331 through grant number N00014-23-1-2685 and contract number N0001423WX01969 under Dr. Yin Lu (Julie) Young as the program manager. 

 

Presenting Author: Geoffrey Warberg The University of Memphis

Presenting Author Biography: Geoffrey Warberg is a second-year Ph.D. student in Mechanical Engineering at the University of Memphis. His research focuses on the material response to cavitation erosion loading. He is part of a NAVSEA Carderock-supported cavitation project conducting near-ship-scale cavitation erosion studies. This project utilizes the William B. Morgan Large Cavitation Channel to achieve a never-before-seen scale of cavitation exposure, enabling realistic near-ship-scale cavitation erosion testing. Geoffrey’s role involves the handling and analysis of cavitation-exposed materials to evaluate the material's response to the tested cavitation conditions. He earned his B.S. in Mechanical Engineering from the University of Memphis and has experience in both industrial and academic research environments.

Authors:

Geoffrey Warberg The University of Memphis
Jin-Keun Choi Naval Surface Warfare Center, Carderock Division
Amir Hadadzadeh The University of Memphis