The Mechanism Of The Flow Control And Noise Reduction Based On The Vortex Generator

When the submarine sails underwater at high speed,The hydrodynamic noise becomes the main noise source,which greatly destroys the submarine's acoustic stealth performance.The vortex generator is a common flow control device in aerodynamics.This paper proposes a method which is based on the vortex generator to control the unstable flow of the submarine's sail hull and reduce the hydrodynamic noise of the submarine.It provides a new idea for reducing the hydrodynamic noise of the submarine from the perspective of flow control.This paper takes the sail hull with part of submarine body as the research object.The flow field is solved by large eddy simulation(LES),The flow-induced noise is solved by the sound analogy and combination of finite element and infinite element.The flow-induced noise characteristics generated by the horseshoe vortex generated at the joint between the sail hull and the submarine body are analyzed.The method of applying a mechanical vortex generator at the junction of the leading edge of the sail hull and the submarine body to reduce the strength of the horseshoe vortex and reduce the flow-induced noise generated by the horseshoe vortex.Micro-vortex generators are applied in the transition zone of the sail hull to control the separation of the boundary layer and reduce the flow-induced noise generated by boundary layer separation and tail vortex shedding.The flow and noise control mechanism of mechanical vortex generator and micro vortex generator is analyzed.By changing the shape of the mechanical vortex generator,the angle with the incoming flow direction,the distance from the leading edge of the sail hull.By changing the angle of attack,angle of incidence and height of the micro vortex generator,the geometric parameters of two types of vortex generators with the best noise reduction effect are determined.On this basis,through the test verification,the hydrodynamic noise of the mechanical vortex generator model was measured by the reverberation method and the turbulent pulsation pressure measurement method in the gravity water hole.The noise reduction capability of the mechanical vortex generator was further evaluated,and the accuracy of the numerical calculation method was verified.The research results of this paper provide a reference for the treatment of submarine hydrodynamic noise,which lays a foundation for the submarine's vibration and noise reduction under high speed conditions.