Experimental and numerical investigation of the centrifugal model for underwater explosion shock wave and bubble pulsation

In this paper, similarity relation between model and prototype based on centrifugal similarity criteria was mainly studied, and it was proved that underwater explosion shock wave and bubble pulsation were in accordance with the centrifugal similarity. First, the similarity criteria of underwater explosion shock wave and bubble pulsation was derived based on n-principle. It shows that when model size is N times smaller than the prototype size, the acceleration of gravity should be expanded N times, so that the model and prototype can meet the similarity relation. Then centrifugal model tests including two different scaled model of 1/20 and 1/30 for the same prototype were conducted through LXJ-4-450 geotechnical centrifuge apparatus. Besides, corresponding model case and prototype case were numerical calculated by LS-DYNA code. The results of test and numerical calculation fit well and various parameters of model and prototype such as peak pressure of shock wave, secondary peak pressure, bubble radius and the period of bubble pulsation fit well too. It was concluded that the underwater explosion bubble pulsation affected by gravity meets the centrifugal similarity criteria and the model experimental study of the bubble pulsation characteristic or the collective effect of the shock wave and bubble should be conducted through centrifuge apparatus.