Current Developments in Mathematical Sciences

Current Developments in Mathematical Sciences

Volume: 2

Liutex-based and Other Mathematical, Computational and Experimental Methods for Turbulence Structure

The knowledge of quantitative turbulence mechanics relies heavily upon the definition of the concept of a vortex in mathematical terms. This reference work introduces the reader to Liutex, which is ...
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The Experimental Study on Vortex Structures in Turbulent Boundary Layer at Low Reynolds Number

Pp. 265-279 (15)

Yanang Guo, Xiaoshu Cai, Wu Zhou, Lei Zhou and Xiangrui Dong

Abstract

Experiments with a moving single-frame and long-exposure (MSFLE) imaging method, which is a Lagrangian-type measurement, is carried out to study the vortex structures in a fully developed turbulent boundary layer at low Reynolds number on a flat plate. In order to give the process of the vortex generation and evolution, on the one hand, the measurement system moves at the substantially same velocity as the vortex structure; on the other hand, a long exposure time is selected for recording the paths of the particles. In the experiment, the vortex structure characteristics as well as the temporal-spatial development can be shown by the streamwise-normal (x-y)-plane and streamwise-spanwise (x-z)-plane images which are extracted from a fully developed turbulent boundary layer. The result shows that the interaction between high- and low-speed streaks induces the generation, deformation and ‘breakdown’ of the vortex structures, and badly influences the vortex evolution.

Keywords:

Boundary layer, High- and low-speed streaks, Low Reynolds number, Moving single-frame and long-exposure time, Vortex structures, Vortex generation, Vortex evolution, Vortex breakdown, Turbulent.

Affiliation:

Institute of Particle and Two-phase Flow Measurement, College of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China