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2015 年 06 月 29 日
Seminar - Simulation of Low Reynolds Number Flows By Dr. Jörg Schlüter

Date: 29 June 2015 (Monday)

Time: 11:00 am – 12:00 pm

Venue: EF305, The Hong Kong Polytechnic University

Abstract:

This talk will include two parts. In the first part the development of innovative
methods for characterizing the mechanical properties of nanowires, nanobelts and
ultrathin films will be introduced. In the second part the fundamental understanding of
deformation mechanisms of a thin film multilayered structure under mechanical loading
and its removal characteristics involved in abrasive machining will be discussed.

The simulation of low Reynolds-number flows is particularly challenging, as regions of laminar, turbulent and transitional flows are present within the flow domain. Yet, a number of technical applications, such as Micro Air Vehicles, wind and marine turbines and miniature gas turbines require the accurate prediction of low-Reynolds number flows.

Large-Eddy Simulations (LES) are a suitable tool to address these issues, as the turbulent motions are resolved in time and space. Transitional flows are inherently well represented as the mathematical formulation of LES reduces naturally to the Navier-Stokes equations, if no turbulence is present in the flow. While for a large range of challenges LES is a powerful tool for the analysis of these flows, for a other applications, LES is computationally too expensive, and models based on Reynolds-Averaged Navier-Stokes equations need to be adapted. Here, LES provides a useful addition to calibrate RANS models.

In my talk, I will present examples of the computational analysis of flapping wings, vertical axis wind turbines and miniature gas turbines using LES and RANS modelling. I will also present some experiments that are devised as validation experiments for these numerical tools. The combination of numerical and experimental analysis allows insights that have not been possible before.

Bio-sketch:

Dr. Jörg Schlüter received his Master’s degree (Dipl.-Ing.) in Engineering Science with a major in Fluid Mechanics from the Technical University Berlin in Germany in 1997. Thereafter, he commenced his PhD studies on the simulation of gas turbine burners at ENSEEIHT/CERFACS in Toulouse, France. After graduating in 2000, he joined as a researcher the Center for Turbulence Research at Stanford University, USA, where he worked on the simulation of entire gas turbine engines. He joined Nanyang Technological University in Singapore in 2005 as an Assistant Professor. Since then, he has worked on a variety of projects ranging from wind turbine engineering, flapping wing aerodynamics to the control of turbulent boundary layers for drag reduction.