Experimental study on time-delay effect of unsteady hydrodynamics of the supercavitating vehicle in water tunnel

The cavity-delay-effect has a significant impact on the tail slapping induced by maneuvering, and it is an important mechanical characteristic of supercavitating vehicles, which must be considered in dynamic modeling. The experimental method of artificial ventilated supercavitation is used in the laboratory of Northwestern Polytechnical University’s high-speed water tunnel to carry out the continuous variable angle of attack experiment. The delay time is quantitatively analyzed by measuring the changes of attack angle and dynamic force with time. Varying delay times are obtained under different conditions, and the dimensionless time-delay coefficient is approximately linearly related to the water speed. The time-delay coefficient increases with the increase of the preset rudder angle. Among the oscillation frequency used in the experiment, the larger the oscillation frequency is, the smaller the time-delay coefficient is.