Experimental study on synchronous high-speed vertical water entry of cylinders

This paper studied the synchronous parallel high-speed vertical water entry of cylinders through experimental methods. The study found that the double cavity exhibited favorable symmetry characteristics during the synchronous parallel vertical water entry of cylinders at the same speed. The outside of the double cavity develops freely, consistent with the single cavity. The lateral spacing deforms the inside contour of the double cavity. The diameter of the inside cavity increases as the lateral spacing increases and gradually approaches that of a single cavity. The cavity length increases with decreasing lateral spacing. In addition, the maximum diameter and length of the cavity increase with the increase in water entry speed under the same lateral spacing. This paper uses the deformation index β to present the double cavity contour prediction model for the water entry process. The model accurately predicts the cavity contour of a synchronous parallel vertical water entry. Additionally, it is deduced that the critical lateral spacing without mutual influence between cavities in this speed range is approximately 7–8D0. The “grass sprouting” splashing development rules were discovered during the synchronous parallel high-speed vertical water entry.