In this talk, the use of active control for flow separation delay and vortex induced vibration (VIV) suppression will be introduced. Here the term "active control" means that the control is realized by injecting a small amount of energy into the existing flow system. Compared to its counterpart, i.e., passive control, active control is adaptive and on-demand, and hence has a much wider operating range. Two types of active flow control methods are presented: one is synthetic jet (SJ) and the other is windward-suction-leeward-blowing (WSLB). Both methods are capable of injecting non-zero momentum into ambient flows with zero net mass flux. Three case studies will be introduced: First, an SJ array is implemented on a low-speed wing to control flow separation so as to improve the wing's aerodynamic performance; Second, a pair of SJ actuators is applied on a circular cylinder to suppress the lift oscillation and hence the one-dimensional VIV; Third, the emerging WSLB concept is adopted to suppress the two-dimensional VIV of a circular cylinder, with the implementation of both open-loop and closed-loop control schemes. In addition, some underlying physics associated with SJ-related flow phenomena will be revealed through various experiments and simulations.

 

 

Dr. Tang Hui is Assistant Professor in Department of Mechanical Engineering, The Hong Kong Polytechnic University. He received his BEng degree in Engineering Mechanics and MEng degree in Fluid Mechanics from Tsinghua University, and his PhD degree in Aeronautical Engineering from The University of Manchester. Prior to joining HK PolyU, he worked in the School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore, and in the Department of Naval Architecture and Marine Engineering, University of Michigan - Ann Arbor. His research interests include aerodynamics/hydrodynamics, active flow control, fluid-structure interaction, and multiphase flow. In these fields he has published more than 50 journal/conference papers.