Committee members

• Prof. Ibrahim Hoteit — Committee Chair
• Prof. Bassam Dally — Ph.D. Advisor
• Prof. Narakorn Srinil — External Examiner
• Prof. Matteo Parsani — ME Committee Member

Abstract

Flow-induced vibration offers a means of harvesting mechanical energy from fluid flows. This dissertation investigates how wake-interference and wake-induced effects can enhance the vibration response and energy-conversion performance of cylinder-based harvesters.

Two configurations are studied: a cylinder–plate system and a cylinder–plate–cylinder system. At a Reynolds number of 150, numerical simulations examine the effects of plate geometry, cylinder spacing, and structural damping. The cylinder–plate system demonstrates enhanced vibration through changes in pressure loading and wake-interference galloping. Coupling wake-interference and wake-induced effects in the cylinder–plate–cylinder system produces seven response regimes. Comparisons with isolated-cylinder and tandem-cylinder systems reveal how spacing and damping influence response amplitude, operating bandwidth, and energy-conversion performance. The preferred configuration depends on whether peak output or performance averaged over the operating range is prioritized.

The investigation is then extended to three-dimensional flow at a Reynolds number of 3900. Comparisons of turbulence models establish SST-DDES as a practical choice for the subsequent multi-body simulations. At the selected spacing and damping conditions, the cylinder–plate–cylinder system sustains strong vibration over a broad reduced-velocity range and achieves approximately higher total overall-averaged power and comparable total overall-averaged efficiency than the tandem-cylinder system. Analysis of fluid forces and wake structures explains the associated energy-transfer mechanisms.

These findings clarify the interaction between wake dynamics, structural response, and energy conversion, and provide guidance for the design of flow-induced vibration energy harvesters.

Short biography

Maojin Gong is a Ph.D. candidate in Mechanical Engineering in PSE division at King Abdullah University of Science and Technology (KAUST), supervised by Professor Bassam Dally. He received his master’s degree in Hydraulic Engineering from Ocean University of China and his bachelor’s degree in Port, Waterway and Coastal Engineering from Ludong University. His research focuses on computational fluid dynamics, fluid–structure interaction, turbulent wakes, and flow-induced vibration for energy harvesting.