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Seminar - Advances in Spray Atomization and Turbulence Theories by Prof. T.-W. Lee
日期:2016 年 10 月 03 日 ( 星期一)
Time:11:00 am – 12:00 pm
Venue:EF305

Abstract:

I will go through a small number of recent theories for spray atomization and turbulence. All of them are based on physical principles in various forms, and involve little or no ad-hoc modelling.

1. Integral formula for determining the drop size in pressure-atomized sprays with and without swirl: prediction of drop size has been a long-standing problem in two-phase fluid mechanics. Many ad-hoc, most of them non-physical, models have been suggested and even are embedded in CFD packages. In this work, we use integral form of the conservation equations, which lead to a closed-form solution for the drop size and its distributions.

2. Cubic formula for the drop size in liquid sprays in cross flows.

3. Integral formula for the Reynolds stress in canonical flow geometries: Closure is considered one of the most difficult problems in fluid physics. Here, we take a unique and simple route that allows for parameterization of Reynolds stress in terms of root turbulence parameters. Again the method is based on principles of fluid physics, and no complex mathematics nor non-physical assumptions are used. Thus are, the results agree well with experimental and DNS results.

4. Compressive sensing for sub-grid scale resolution of turbulent flows.

Fig. 1. Comparison of the Reynolds stress in rectangular channel flow with DNS data.

 

2. Compressive sensing for reconstruction of sub-scale features in turbulence

Bio-sketch:

Prof. Lee is a Professor in Department of Mechanical and Aerospace Engineering, Arizona State University, in what is now called the “School of Engineering for Matter, Transport, and Energy”, which potentially studies everything in the universe. His research interests include wide-ranging problems based on robust applications of thermal-fluid physical principles, e.g. urban heat island, spray atomization, turbulence, complex bio-chemistry, earth climate systems, and so on. He has published many papers on these subjects, and also couple of decent textbooks (Aerospace Propulsion, Wiley; Thermal and Flow Measurements, CRC Press).