Numerical Simulation of Flow-induced Vibration of Rigid and Flexible Structures: Using Overset Mesh Technique

Abstract

This project focuses on the numerical study of flow-induced vibration (FIV) in both rigid and flexible structures, employing the finite-volume method for both fluid and solid domains. The study employs advanced numerical techniques tailored for both rigid and flexible structures, leveraging sliding and deformable overset mesh methods to address the limitations of traditional dynamic mesh approaches. For rigid structures, cost-effective RANS models are combined with sliding overset meshes to efficiently simulate vortex-induced vibrations (VIV), while for flexible structures, deformable overset meshes are developed to accommodate significant structural deformations. These techniques reduce overall grid-size requirements, maintain high-quality near-wall resolution even at large oscillation amplitudes, and ensure computational stability and improved solution fidelity. The research utilizes the open-source platforms OpenFOAM, solids4Foam, and preCICE for two-way fluid-structure interaction (FSI) coupling, enabling reliable simulations of complex FIV scenarios across a wide range of applications. To validate the proposed framework, three sets of two-way coupled cases are compared against experimental data from the literature: flow around a stationary cylinder, vortex-induced vibration of a rigid cylinder, and flow-induced vibration of a flexible cantilever cylinder. There are four resulting original outcomes. The first breakthrough concerns the physical modelling of flow around static and oscillating bodies. By making the turbulent viscosity coefficient of the Launder-Sharma 𝑘 − 𝜀 model sensitive to the strain rate invariant, this extended version of the Launder-Sharma model provides improved predictions of the flow field, showing reasonable agreement with available experimental data. Furthermore, it reliably captures vibration amplitudes and frequencies over the entire range of available data. This extended version of the Launder-Sharma model therefore appears to offer a highly cost-effective approach for simulating flow-induced vibrations. Secondly, regarding the numerical solution strategy, this study demonstrates that the use of moving overset meshes to track the movement of the oscillating cylinder provides a highly effective simulation approach. Thirdly, additional simulations using this validated modelling strategy have, for the first time, decoupled the effects of the flow Reynolds number from a previously overlooked dimensionless parameter related to the spring constant. The results reveal that this parameter has a far greater influence on flow-induced vibrations than the Reynolds number. Finally, the potential of the deformable overset mesh method has been validated through its successful application to two-dimensional cases and further explored through preliminary simulations of three-dimensional studies.

Date of Award	12 May 2025
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Hector Iacovides (Supervisor) & Timothy Craft (Supervisor)