Study of sheet cavitation on a pitching hydrofoil

The dynamic cavitation on a moving wall is garnering increasing interest because many fluid machinery systems operate under dynamic conditions in real-world scenarios. This study adopts a numerical method to investigate sheet cavitation on a pitching hydrofoil with the objective of elucidating the dynamic behaviour of the cavity and its influence on hydraulic performance. The results show that dynamics of the sheet cavity on the up-pitching hydrofoil exhibit significant delay effects. Within the downstroke phase from the maximum to the mean angle of attack, the features of the sheet cavity on the pitching hydrofoil are close to those on the stationary hydrofoil. However, the swift pitching action of the hydrofoil can result in a rapid fluctuation in the second derivative of the cavity area. The hydrofoil consistently experiences a significant reduction in lift and an increase in drag.