Unsteady Load Analysis of Partial Cavitation of a Hydrofoil at High Reynolds Numbers

Cavitation is the primary cause of erosion on lifting surfaces and ship propellers. In real-world conditions, the Reynolds number on a marine hydrofoil typically reaches millions, and surface pressure fluctuates frequently and with high magnitude, making the hydrofoil prone to structural damage. This study investigates the unsteady loads of partial cavitation using large eddy simulation over a modified NACA-16 hydrofoil at various angles of attack, cavitation numbers, and high Reynolds numbers from 1.4 to 50 million. The Schnerr-Sauer cavitation model and a two-phase flow approach based on the volume of fluid method are employed. The computational domain matches the dimensions of the Large Cavitation Channel with a test section of 3.05 by 3.05 by 13.1 meters. To validate the method, the pressure distribution and global forces are compared with previous experimental data. Additionally, a small tripping fence is added near the leading edge of the hydrofoil to improve the uniformity of cavitation generation. The cavitation aggressiveness is assessed, and regions on the hydrofoil with a high risk of erosion are estimated. While the fence increases the spanwise uniformity of the cavity, it can increase the time-averaged drag coefficient. Statistical analysis shows strong agreement between the frequency content of forces and experimental data. Overall, the method performs very well across the range of conditions investigated.