An immersed boundary method for modeling fluid–solid–acoustic interactions involving dynamic structures

Abstract

In equipment within the aviation and marine industries, aerodynamic and hydrodynamic noises generated by the coupling effect between moving structures (such as equipment shells, landing gears, blades, etc.) and fluid media are ubiquitous. These noises significantly impact the noise levels of the equipment and its surrounding environment, posing threats to the health of users and organisms in the environment. While existing noise calculation methods effectively address aerodynamic and hydrodynamic noises from fixed structures under uniform incoming flow conditions, few literatures delve into the computational methods for aerodynamic and hydrodynamic noises arising from the interaction between moving structures and fluid media. To calculate fluid noises induced by structural vibrations and motions, this paper proposes an immersed boundary method for fluid–structure–acoustic interactions with moving structures. This method concurrently employs the Navier–Stokes equation and wave equation to describe the time-averaged quantities and fluctuating variables of the fluid, taking into account the influence of non-uniform fluids during sound propagation. Based on this methodology, noise tests and numerical calculations were conducted on vibrating cylindrical shells, along with fluid–structure–acoustic coupling calculations for linearly moving cylinders in static fluids. These examples validate the effectiveness and accuracy of the proposed method in simulating the generation and propagation processes of radiation noise and flow-induced noise caused by structural motion.