MAE Seminar: Time-Resolved Non-intrusive Pressure Measurement Technique and its Applications

McDonnell Douglas Engineering Auditorium
Professor Xiaofeng Liu

Assistant Professor
Department of Aerospace Engineering and Engineering Mechanics
San Diego State University

Abstract: Pressure distribution plays a crucial role in determining flow phenomena and system performance for a variety of applications involving fluid flow. Because of the importance of the pressure information in flow fields, efforts in developing non-intrusive pressure measurement techniques, e.g., pressure PIV, have been actively carried out in the past decade in the fluids community. In this talk I will review the history of the development of pressure PIV, with an emphasis on the description of the principle of material acceleration measurement and the evolution of the omni-directional-integration techniques for pressure reconstruction. Sample applications of time-resolved pressure PIV in cutting-edge research areas such as turbulence, acoustics, cavitation and flow-structure interaction will be illustrated using a detailed investigation of a cavity-shear layer flow as an example. Elucidation of the mechanism for the low-frequency self-sustained flapping of the cavity-shear layer by the time-resolved pressure PIV, which is responsible for the well-known “buffeting” phenomenon in cavity flow, will be highlighted in the presentation. In addition, an update on research projects currently conducted at the new laboratory for advanced experimental fluid dynamics at San Diego State University will be presented. These projects include development of a novel parallel ray omni-directional integration algorithm for pressure field reconstruction, quantification of the effect of the limited measurement resolution on the accuracy of pressure measurement using the JHU DNS turbulence database, establishment of 3-D tomographic PIV and pressure measurement capability, and design and construction of a new water tunnel research facility. 

Biography: Xiaofeng Liu, an associate fellow of the AIAA, is currently assistant professor in the Department of Aerospace Engineering and Engineering Mechanics at San Diego State University. Before joining SDSU, he was first a postdoctoral fellow and, later, an assistant research scientist and adjunct principal research engineer in the Department of Mechanical Engineering at Johns Hopkins University. He received a bachelor's and master's degree in aerodynamics from Beijing University of Aeronautics and Astronautics and a Ph.D. in aerospace engineering from the University of Notre Dame. Prior to coming to the U.S. for his doctorate, he was a lecturer in the Department of Engineering Mechanics at Tsinghua University. Before joining the Tsinghua faculty, he was a project manager in the Division of International Cooperation at the China Academy of Launch Vehicle Technology. Liu’s research expertise includes experimental fluid dynamics, high-lift aerodynamics, turbulent-shear layer flows, wake flows, vortex dynamics, cavitation, flow-structure interactions, acoustics, evaporative cooling and heat transfer, image processing and development of optics-based pressure field measurement techniques. 

Liu is a member of the AIAA Aerodynamic Measurement Technology Technical Committee and an active member in the American Physical Society, American Society of Mechanical Engineers. He was a keynote speaker at the International Workshop on the Application of Particle Image Velocimetry for Aeroacoustics and Noise in 2012. He has given numerous invited lectures at universities both in the U.S. and overseas. He is also an active reviewer for academic journals including Physics of Fluids, Experiments in Fluids, Journal of Fluids Engineering, Physica D, Journal of Aircraft, International Journal of Flow Control, Computers and Fluids, and Advances in Applied Mathematics and Mechanics.