EXPERIMENTAL STUDY ON FLUCTUATING HYDRODYNAMICS AROUND AXISYMMETRIC BODIES

In order to study the fluctuating hydrodynamics around axisymmetric bodies, the unsteady characteristics of cavitating flows around hemispherical and blunt bodies are investigated experimentally. Experiments are carried out in a rectangular test section of a cavitation tunnel. A high-speed video camera and dynamic force measurement system are used to record the unsteady cavitating flow patterns and the resistance of axisymmetric bodies under different cavitation conditions. Also, the fluctuating hydrodynamic characteristics are obtained. The results show that cavity shapes reveal the miscellaneous patterns of flow and interface in different development stages, which are strongly correlated with unsteady dynamics characteristics. Frequency characteristics of the unsteady cavitating flows are different around different hemispherical blunt bodies. For the blunt axisymmetric bodies, the frequency characteristics of the low-frequent pulsation are mainly due to the large-sale 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.