Part B: numerical investigation of unsteady supercavitating flows



The present numerical study is the second part of an investigation of unsteady cavitating flows. In the first part, cavity formation, establishment and disappearance were recorded using a high speed camera. Cavitation bubble length and diameter were extracted in accelerating and decelerating phases of model flight. Comparison of the experimental results with those of the steady state flow field solution showed an unacceptable agreement. In the present study a more realistic unsteady cavitating flow field simulation of the first part of the experiments is performed. The actual velocity variation of the experimental test is used in a dynamic mesh, unsteady flow field solution. Numerical results including the length and diameter of partial cavitation bubble in the accelerating phase had fairly good agreement with the experimental results. This is in contrast to the steady numerical results presented in the first part, which had a significant difference with the experiments. The maximum error of the length and diameter of the supercavitation bubble of the first part of the experimental and present numerical results is less than 10%, while the usual steady results are totally unacceptable.