Department News
Flow Visualization in Turbulent Large-Scale Structure and Flow Control Researc
Seminar Date
2003-11-06
Author
안지영
Date
2003-11-06
Views
1662
1. 제 목 : Flow Visualization in Turbulent Large-Scale Structure and Flow Control Research
2. 연 사 : Professor Lorenz W. Sigurdson Mechanical Engineering Department, University of Alberta, Canada
3. 일 시 : 2003년 11월 12일 (수) 오후 5시
4. 장 소 : 301동 117호 세미나실
내 용 :
It is now generally accepted that most turbulent shear flows have a characteristic large-scale structure (LSS). The resulting task is to determine what the LSS is for any particular flow that one is interested in modeling or controlling. If it is not a well studied flow where the LSS is already known, then the wisest course of action is to learn what the LSS is using the most efficient techniques at your disposal. Careful use of experimental flow visualization is one of the quickest, cheapest, and surest ways to discover the qualitative nature of the flow LSS. Although significant progress has been made in using evolutionary algorithms to find optimum control techniques, in actual application one must have an idea what levers are at one's disposal before one can devise practical control manipulators. One needs to know the geometric nature of the LSS that are expected to occur, and in what frequency ranges. Forcing techniques can then be designed to produce flow perturbations that will be amplified by, or negate the naturally occurring LSS, depending on the desired outcome. This article will discuss some of the LSS studied at the Vortex Fluid Dynamics Lab (VFDL) using various flow visualization techniques, and the effect that open loop control methods have been shown to have. The flows discussed are: synthetic jet control of a jet in cross-flow, inadvertent pulsation influence on orifice plate flow meters, and another type
of synthetic jet we call the "synthetic fence jet".
2. 연 사 : Professor Lorenz W. Sigurdson Mechanical Engineering Department, University of Alberta, Canada
3. 일 시 : 2003년 11월 12일 (수) 오후 5시
4. 장 소 : 301동 117호 세미나실
내 용 :
It is now generally accepted that most turbulent shear flows have a characteristic large-scale structure (LSS). The resulting task is to determine what the LSS is for any particular flow that one is interested in modeling or controlling. If it is not a well studied flow where the LSS is already known, then the wisest course of action is to learn what the LSS is using the most efficient techniques at your disposal. Careful use of experimental flow visualization is one of the quickest, cheapest, and surest ways to discover the qualitative nature of the flow LSS. Although significant progress has been made in using evolutionary algorithms to find optimum control techniques, in actual application one must have an idea what levers are at one's disposal before one can devise practical control manipulators. One needs to know the geometric nature of the LSS that are expected to occur, and in what frequency ranges. Forcing techniques can then be designed to produce flow perturbations that will be amplified by, or negate the naturally occurring LSS, depending on the desired outcome. This article will discuss some of the LSS studied at the Vortex Fluid Dynamics Lab (VFDL) using various flow visualization techniques, and the effect that open loop control methods have been shown to have. The flows discussed are: synthetic jet control of a jet in cross-flow, inadvertent pulsation influence on orifice plate flow meters, and another type
of synthetic jet we call the "synthetic fence jet".
