Youngdon Kwon
Sungkyunkwan University · 化学工学
研究室紹介
Professor Youngdon Kwon's research lab specializes in the theoretical and computational modeling of complex fluid dynamics, with a focus on viscoelastic fluids and polymer rheology. The lab investigates nonlinear behaviors in viscoelastic flows, including instabilities such as melt fracture, sharkskin effects, and bifurcations in shear and elongational flows, using advanced constitutive equations like Leonov, Giesekus, and Larson models. A key emphasis is placed on developing robust numerical methods—such as tensor-logarithmic formulations and decoupled time integration—for simulating highly nonlinear and unstable flow regimes in complex geometries. The lab also explores molecular-level dynamics, including end-association in telechelic chains and dielectric relaxation in dipole-inverted chains, linking macroscopic rheological behavior to microscopic chain dynamics.
Research Overview
Research Output Trend
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Selected Papers
15Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Youngdon Kwon, Kwang Soo Cho; Time-strain nonseparability in viscoelastic constitutive equations. J. Rheol. 1 November 2001; 45 (6): 1441–1452. https://doi.org/10.1122/1.1413505 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefW
For dilute telechelic linear and ring Rouse chains undergoing reversible end-association and dissociation, the time ( t ) evolution equation was analytically formulated for the bond vector of the subchain (or segment), u [c] ( n, t ) with n being the subchain index and the superscript c specifying the chain (c = L and R for the linear and ring chains). The end-association of the linear chain (i.e., ring formation) occurs only when the ends of the linear chain come into close proximity. Because o
One-dimensional (1D) instabilities, some of them of new type, were found in simple shear and simple elongation for Giesekus, Leonov, and Larson viscoelastic constitutive equations (CEs) with single relaxation mode. Whereas 1D instabilities in shear flow were found for all three CEs, only the Larson model manifested some 1D instabilities (and even nonexistence of solution) in simple extensional flows.
In the finite element framework, we employ decoupled time integration scheme for viscoelastic fluid (the Leonov model) flow and then investigate highly nonlinear behavior in 2D creeping contraction flow. In the analysis of steady solutions as a preliminary study, the results are shown to be free from frustrating mesh dependence when we incorporate the tensor-logarithmic formulation [Fattal and Kupferman, J. Non-Newtonian Fluid Mech. 123, 281–285 (2004)]. Two kinds of elastic fluid have been chos