航空与力学名家讲坛10月17日下午报告会预告

报告人： Junde Li Victoria University, Australia(Currently on leave at Tsinghua University)

报告时间：2014年10月17日（周五）下午14:30

报告地点：流体所214

报告摘要：

Hot-wire and its anemometers have been used for turbulence measurements in air flows over many years. So far, all the verifications of the classical theoretical results of turbulence rely on the experimental results from hot-wire measurements. Hot-wire and its anemometers are still widely used today because of its high temporal resolution and reasonable spatial resolution. In using hot-wire and its anemometers for turbulence measurements, the spatial resolution and the lack of theoretical solutions for its dynamic response are two issues which have limited our ability to use it with full confidence. Here, the length to diameter ratio of the hot wire, which is directly related to its spatial resolution, is presented first using numerical results. It is found that the minimum length to diameter ratio of the hot wire depends on the materials of the hot wire and the Reynolds numbers and should not be a fixed value. The theoretical solution of the hot wire and its anemometers are then presented. It is shown that an attenuation of the hot wire exists and starts from a fairly low frequency, depending on operational parameters. It is shown that the effect of this attenuation on the measurements of second order statistics of turbulence may be small, its effect on high order structure functions can be significant. A method of correcting this hot-wire attenuation effect is proposed.

报告人简介：

1977年恢复高考后第一批考进清华大学的水利系水轮机专业。1982年初参加清华大学的研究生考试被教育部选为出国预备生，并于1984年被派往澳大利亚读研究生。1984年开始在国际知名流体力学专家，A.E. Perry 教授的指导下在澳大利亚的墨尔本大学攻读博士学位，并于1989年取得博士学位。1989-1991年间，在墨尔本大学做研究员助理。 1992-1994年在悉尼大学做Research Fellow。 1995年，被澳大利亚的维多利亚大学聘为讲师，并相继被提升为高级讲师，副教授，教授。1999年到美国的普林斯顿大学做了半年的访问研究员。2014 的下半年，在清华大学做高级访问学者。