Vibration characteristics of a hydraulic buoyancy regulator considering the fluid-structure interaction

The hydraulic buoyancy regulator (HBR) is one core component of large unmanned underwater vehicles (LUUV). The vibration of the HBR directly affects the stealth and detection performance of the LUUV. A dynamic modeling method considering the fluid-structure interaction (FSI) is proposed to investigate the vibration characteristics of a HBR. The effect of the FIS on the vibration of the HBR are simplified as the added mass and equivalent fluid damping in the proposed method. The calculation efficiency and accuracy of the proposed method are verified by comparing with the results from the two-way FSI method and Morison method. The calculation time is reduced to about 1/3 of that required by the two-way FSI method. The effects of the fluid and hydraulic oil temperature on the vibration characteristics of the motor-pump unit (MPU) and HBR are conducted by using the proposed method. Note that the lower hydraulic oil temperatures enable the MPU and HBR under the forced vibration condition to reach the steady state more rapidly because of the greater fluid damping energy dissipation. The vibration characteristics of the MPU and HBR under different frequency excitations are also analyzed by using the proposed method. This work can provide some inspiration and guidance for the vibration analysis of the hydraulic buoyancy regulators considering the FSI.