Date: Wed Aug 10th, 2022, 10:30 AM
Room: ASTC #615 (첨단과학기술연구관(117동) 615호)
Speaker: Jeonglae Kim, Ph.D. (Assistant Professor, School for Engineering of Matter, Transport & Energy, Arizona State University)
Title: Analyzing turbulence using wavelet
Abstract: The classical description of turbulence is rooted in scale-based arguments formulated in the Fourier spectral space. However, the geometric and physical complexities arising in turbulent flows call for alternative approaches. Even for homogeneous turbulence, it is well known that spatially local events are dynamically significant. This is pronounced if sharp interfaces are present such as flame fronts, shock waves, and fluid--fluid boundaries exchanging mass, momentum, and energy in two ways with turbulence. It is argued that scale alone is insufficient to characterize turbulent flows in nonequilibrium, multiphysical setups, highlighting the limitation of Fourier-based theories lacking spatial information. In large-eddy simulation (LES) where the two-way interactions are modeled, the limitation becomes more serious. This presentation demonstrates the capabilities of wavelet for characterizing turbulent flows interacting in two ways with monodispersive, point, inertial particles. Wavelet localizes analysis simultaneously in scale and space. Wavelet analysis is extended for analyzing the turbulence kinetic energy transport across scales and between different phases. The formulation is applied to configurations where particles are clustered preferentially at high concentration. Consistency and discrepancy with the traditional descriptions of particle-laden turbulence are discussed as well as LES modeling suggestions for two-way coupled particle-laden turbulence.
Speaker Bio: Dr. Jeonglae Kim is an assistant professor in the School for Engineering of Matter, Transport and Energy at Arizona State University (ASU). He received both B.S. and M.S. degrees at Seoul National University and Ph.D. in Theoretical & Applied Mechanics at University of Illinois at Urbana-Champaign. Before joining ASU, he was a post-doctoral research associate at Cornell University and later a post-doctoral fellow in the Center for Turbulence Research at Stanford University. At ASU, Dr. Kim is interested in simulating, analyzing, and modeling turbulent flows and their two-way interactions with multiphysical effects such as chemical reaction, inertial particles, and polymer suspension. For those studies, Dr. Kim develops novel large-eddy simulation tools, wavelet framework, and data-driven modeling approaches. Dr. Kim's research also includes acoustics/aeroacoustics and flow control.