Turbulent flow development and the noise reduction mechanism by the groove surface
QU Junchao, LIU Yongwei*, SHANG Dejiang
(Acoustic Science and Technology Laboratory, Key Laboratory of Marine Information Acquisition and Security(Harbin Engineering University), Ministry of Industry and Information Technology,College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, Heilongjiang, China)
Abstract:
The hydrodynamic noise is the main noise source of underwater vehicles at high speed and destroys its acoustic stealth performance. The SUBOFF sail hull and submarine body model is selected as the research object. The unsteady flow near the sail hull has been numerically calculated. The unstable flow phenomenon caused by the flow through the sail hull has been analyzed. The noise generation mechanism has been summarized. A new method of the hydrodynamic noise control is proposed, based on the shark skin groove. The grooves are formed in the joint between the sail hull and the submarine body. The mechanism of control turbulent development and noise reduction by the groove surface has been studied. The results have shown that the grooves can suppress the boundary layer separation, inhibit the generation of horseshoe vortex, and reduce the low frequency line spectrum noise generated by the horseshoe vortex. The results have also shown that the noise reduction level increases with the increase of the groove′s depth. The maximum noise reduction of the model can be achieved by 13 dB in the paper.
KeyWords:
grooves; flow control; hydrodynamic noise
