Experimental study on fluctuating hydrodynamics around axisymmetric bodies

Cavitating flows around axisymmetric bodies are studied based on the experiments and numerical simulations. In experiments, a high-speed video camera is used to visualize the flow structures for different axisymmetric bodies and cavitation numbers, and a dynamics measure system is used to measure the instantaneous dynamic characteristic of the axisymmetric bodies. Meanwhile, a density modify based closure model for unsteady cavitating flows which contains multi-phase and time scale information of the cavitating flows is used. Comparisons are made with available measurements of surface pressure distribution to validate the methods. It is shown that the nature cavitation phenomenon around the axisymmetric bodies can be well simulated. There are different miscellaneous patterns of flow and interface for distinct shape bodies, which are strongly correlated with unsteady dynamics characteristics. The differences exist between frequency characteristics of the unsteady cavitating flows around hemispherical and blunt bodies. For the blunt axisymmetric bodies, the frequency characteristics of the low-frequent pulsation seems due to the large scale cloud shedding and is different from the pulsation caused by the local breakup of the cavity at its tail zone of the hemispherical axisymmetric body.