Influence of flow velocity and flexural rigidity on the flow induced vibration and acoustic characteristics of a flexible plate

Abstract

A numerical investigation on the influence of structural flexibility and flow velocity on the flow-induced acoustic and vibration response of a plate is presented. Simulations are performed on a test geometry of rigid square bluff body with a trailing flexible plate in low Reynolds number flow stream. The focus of the study is to characterize the flow-induced vibration and associated aerodynamic far field sound radiation from a flexible structure in flow. The role of flow velocity and level of structural flexibility on the acoustic radiation is thoroughly investigated. A linearized Euler equation based computational aeroacoustic hybrid method and a surface source approach for coupling the flow and acoustic domains are implemented with a bi-directional fluid structure interaction. The vortex shedding frequency of the coupled fluid-structure system synchronizes with the fundamental frequency of the trailing plate and steady-state vibration of the plate is observed. The results indicate that the relation between vibration level and the flow velocity as well as structural flexibility is not linearly related. For a particular combination of flow velocity and plate stiffness, the coupled fluid-structure system shows the resonance condition. The observed resonance frequency is slightly different from the free vibration (natural) frequency of the plate. Computation of the acoustic shows that the magnitude and spectral nature of the far field sound depends on the amplitude of the vibration and a higher acoustic pressure and the sound rich in tones is observed at resonance condition.

Hydrodynamic characteristics of flow past a circular cylinder with four attached flexible plates in a high Reynolds number turbulent flow

“…Also, the high structural stiffness values made a permanent vibration frequency closer to the first natural frequency of the structural stiffness. Purohit et al (2018) examined a flexible plate attached to a square cylinder in a laminar flow. In this case, the impacts of flexural rigidity and fluid velocity have been investigated on plate oscillations.…”

Study on dynamics responses and applications of non-uniform beam structure under crosswind

“…As far as we know, there is little research work on the dynamic responses and vibration applications (vibration control, stability enhancement, and energy harvesting) of nonuniform beam structures under the crosswind. Considering the response under the crosswind, the engineering structure (cylinder, plate, cable, and beam) will generate vortex shedding, which produces harmonic dynamic excitations (Facchinetti et al, 2004; Martins and Avila, 2019; Mehmood et al, 2014; Purohit et al, 2018) as a kind of oscillatory flow (Kurushina et al, 2018; Su and Lin, 2020). When vortex shedding from both sides of slender structure periodically, it will produce periodic lift force on the structure.…”