AEROSPACE ENGINEERING

Abstract

Most fish swim by undulating their body in the form of backward (opposite to the swimming direction) traveling waves. Traveling waves are found to keep the flow attached to the swimmerʼs body and reduce the turbulent intensity of the flow. Inspired by these observations, the utility of backward traveling waves (which can be generated through piezoelectric actuators) for flow control was numerically investigated. Large eddy simulations of flow over an inclined undulating plate and an airfoil were performed using the curvilinear immersed boundary method (CURVIB). It was found that the wave speed is not the only parameter for flow reattachment, but both wavelength and frequency individually impact flow separation by affecting two competing but interconnected mechanisms: the streamwise momentum, imparted onto the fluid by the undulations, tends to reattach the flow but the lateral velocity tends to detach it. In addition, imposing traveling wave on the suction side of the are found to be more effective in reducing flow separation than other types of oscillations, including forward traveling waves and standing waves. At the end, traveling waves are shown to reduce shocks in a supersonic turbulent channel flow.

Speaker

Dr. Iman Borazjani

Associate professor at the J. Mike Walker ʼ66 Department of Mechanical Engineering at Texas A&M. He got his Ph.D., MSc, and BSc degrees in mechanical engineering from the University of Minnesota, Georgia Tech, and Sharif University in 2008, 2005, and 2002, respectively, and was a post-doctoral researcher at the St. Anthony Falls Laboratory, University of Minnesota. He is the recipient of the 2013 Scientific Development Award from the American Heart Association, and the 2013 Doctoral New waves. Chemical Society, 2015 NSF
CAREER, and 2018 Fulbright award. He is a fellow of ASME and an associate fellow of AIAA.