Vortex-induced and/or galloping vibrations occur when fluid flows across structures that may be of square or circular section or any other shape. While a single square cylinder may experience galloping vibrations, a single circular cylinder does not. When the wake of a single structure is very complex, characterized by many fascinating phenomena, the flow interference between the two structures makes the wake more complex, leading to very high fluctuating forces, structural vibrations, acoustic noise, or resonance, which in some cases can trigger failure. As such, although a single circular cylinder does not experience galloping, two circular cylinders in close proximity do. Two square cylinders in close proximity may have an opposite scenario. This lecture will encompass galloping vibration problems associated with two square cylinders, casting light upon the mechanisms behind the galloping vibration and its sustainability. In addition, the roles of added mass and added damping, and physical aspects in the process of initiating the vibration will be paid attention to. The vibration response and mechanism of two tandem square cylinders are studied at Reynolds number Re = 100 and 200. Two scenarios are considered: case I, upstream cylinder fixed and downstream cylinder vibrating; case II, upstream cylinder vibrating and downstream cylinder fixed (Fig. 1). The obtained results are compared with the vibration of a single square cylinder.

Alam Md. Mahbub is a professor at Harbin Institute of Technology (China) since 2012. He worked as a senior lecturer at the University of Pretoria (South Africa), research and postdoctoral fellows at the Hong Kong Polytechnic University, and lecturer at the Rajshahi University of Engineering and Technology (Bangladesh). More than 325 technical articles are authored and co-authored, including 150 SCI journal papers. Most of the papers have been published in the top-notched journals, including Journal of Fluid Mechanics, Journal of Fluids & Structures, Ocean Engineering, Physics of Fluids, and Journal of Sustainable and Energy Reviews. His papers are well-cited, 3783 (h-index 35) in WoS database and 5752 (h-index 41) in the google database. He has been listed as a highly cited researcher for 2018 - 2021 (single year) by Web of Science, ranked top 2%. He is the author of two books. He has edited four special issues in ‘Wind and Structures, an International Journal’. He has delivered 23 Keynote speeches at international conferences. His research has mostly involved flow-induced vibrations, bluff-body wake, wind load on structures, fluid-structure interactions, hydrodynamics of swimming animals, flow control, and energy harvesting from wind and ocean current. 
Prof Alam has received a number of awards: Japan Government Scholarship (monbusho) for Masters and PhD studies; JSPS (Japan Society for Promotion of Science) Postdoctoral fellowship; South Africa National Research Foundation (NRF) rating ‘Promising Young Researcher, Y1’; China 1000-young-talent scholar; Shenzhen High-Level Overseas Talent; 2015 Shenzhen Outstanding Teacher; and 2017 Nanshan-District High-Level Talent. He is an editorial board member of ‘Wind and Structures, an International Journal’.