Study on the Characteristic of Natural Cavitation with Large Cavitation Number

In order to study the cavitation characteristics of natural cavitation, a natural cavitation was investigated using three-dimensional numerical simulation and cavitation water tunnel experiments under the condition of large cavitation number. The radius of cavitation longitudinal plane and length of cavitation are derived based on the principle of independent expansion of cavitation section and the momentum theorem. The cavitation experiments are carried out by using the blunt body model in K15 cavitation water tunnel at the cavitation number of 0.2, 0.4, 0.6 and 0.8. Besides, the mixture multiphase flow model and Schnerr and Sauer cavitation model were used to simulate the same conditions as the experimental environment. Compared with the theoretical results of Эпштейн, Гузевский and Логвинович, they are basically similar. The range of cavitation number for each theoretical formula is put forward, and numerical example is given to illustrate it. Results of simulation are consonant with the experiment. In simulation, it could be find that the rear end of the cavitation will contract inward when the cavitation number is large, which further shows that the ellipse hypothesis is not applicable to rear end of the cavitation. The study of natural cavitation characteristics is of great significance to the design of underwater moving bodies.