Similarity test method and similarity test system for cross-medium water inlet and outlet reduced scale ratio model

The invention belongs to the field of a cross-medium water inlet and outlet test of a water inlet and outlet reduced scale model, and particularly relates to a similarity test method and a similarity test system of the cross-medium water inlet and outlet reduced scale model. Determining satisfaction conditions of hydromechanics in the supergravity environment in similar conditions of the water inlet and outlet reduced scale ratio model test; determining a cavitation number and a gas density coefficient under similar conditions in the supergravity environment; determining a Reynolds number in similar conditions in the supergravity environment; determining the gas nucleus density under similar conditions in the supergravity environment; determining a Weber number in similar conditions in the supergravity environment; and based on similar conditions of fluid mechanics, a cavitation number, a gas density coefficient, a Reynolds number, a gas nucleus density and a Weber number in the supergravity environment, obta