Les Study On the Relationship Between Large-scale Turbulence Vortices and Unsteady Cavitation Around a Hydrofoil


 We conducted a large-eddy simulation (LES) of cavitating turbulent flow around a Clark-Y11.7% hydrofoil at an angle of attack of 8 degrees. We focused on the improvement of the reproducibility of hydrofoil performance under cavitating conditions when considering the unsteadiness of the flow field sufficiently by LES. A homogeneous cavitation model was adopted. The subgrid-scale model for LES was the one-equation dynamic model. The unsteady phenomena such as cavity oscillation and cloud cavity shedding accompanied by the re-entrant jet were simulated. Large-scale spanwise vortices were also captured, which occurred intermittently from the onset of the sheet cavity. Then, the flow inside the sheet cavity was deaccelerated and the streamlines went around the sheet cavity. Streamline curvature formed a separation bubble behind the sheet cavity accompanied by a low-pressure region. Thus, the sheet cavity length was sufficient and the reproducibility of the pressure distribution around the hydrofoil and lift coefficient were improved.