Department News
Do large-scale coherent structures affect subgrid scale quantities in turbulent
Seminar Date
2004-06-09
Author
임아주
Date
2004-06-09
Views
1744
1. 제 목 : Do large-scale coherent structures affect subgrid
scale quantities in turbulent shear flow?
2. 연 사 : 강형석 박사
Department of Mechanical Engineering,
Johns Hopkins University
3. 일 시 : 2004년 6월 25일 (금) 16:00
4. 장 소 : 301동 1512호 세미나실
5. 내 용 :
The dynamical interplay between large and small-scale structures is central to the energy cascade in turbulent flows. This interplay is also of interest in the context of Large Eddy Simulations (LES), where the response of small-scale structures to given resolved turbulent fields, or large-scale structures, must be parameterized. Among the phenomena characterizing the large scales of turbulent flows, coherent structures are the most ubiquitous, as can be inferred from a rich body of literature. The main objective of this study is to explore the effect of large-scale coherent structures on the subgrid scale (SGS) physics in a turbulent shear flow. Other related objectives are to document possible differences between SGS kinetic energy and scalar-variance dissipations, and to compare eddy-diffusion and nonlinear model predictions. The issues of "isotropy" and "universality" in the specific context of subgrid scale dissipations and modeling for LES are also addressed. This study is based on data from two flows that contain well-defined large-scale structures. The first is the cylinder wake flow at high Reynolds number, and the measured data include periodic von Karman vortices. The second is the Kolmogorov flow simulated at low Reynolds number, which includes an array of counter-rotating large-scale coherent vortices as a response to an imposed large-scale forcing. The experimental and DNS results will be compared, and the specific answers for the objectives will be given in the presentation.
6. 문 의 : 기계항공공학부 최 해 천 교수 (☏ 880-8361)
scale quantities in turbulent shear flow?
2. 연 사 : 강형석 박사
Department of Mechanical Engineering,
Johns Hopkins University
3. 일 시 : 2004년 6월 25일 (금) 16:00
4. 장 소 : 301동 1512호 세미나실
5. 내 용 :
The dynamical interplay between large and small-scale structures is central to the energy cascade in turbulent flows. This interplay is also of interest in the context of Large Eddy Simulations (LES), where the response of small-scale structures to given resolved turbulent fields, or large-scale structures, must be parameterized. Among the phenomena characterizing the large scales of turbulent flows, coherent structures are the most ubiquitous, as can be inferred from a rich body of literature. The main objective of this study is to explore the effect of large-scale coherent structures on the subgrid scale (SGS) physics in a turbulent shear flow. Other related objectives are to document possible differences between SGS kinetic energy and scalar-variance dissipations, and to compare eddy-diffusion and nonlinear model predictions. The issues of "isotropy" and "universality" in the specific context of subgrid scale dissipations and modeling for LES are also addressed. This study is based on data from two flows that contain well-defined large-scale structures. The first is the cylinder wake flow at high Reynolds number, and the measured data include periodic von Karman vortices. The second is the Kolmogorov flow simulated at low Reynolds number, which includes an array of counter-rotating large-scale coherent vortices as a response to an imposed large-scale forcing. The experimental and DNS results will be compared, and the specific answers for the objectives will be given in the presentation.
6. 문 의 : 기계항공공학부 최 해 천 교수 (☏ 880-8361)
