[기계] Granular Flows

1. 제 목 : Granular Flows

2. 연 사 : Hojin Ahn, Ph.D.

3. 일 시 : 2008년 8월 13일(수) 16:00~ 17:00

4. 장 소 : 301동 1512호

5. 내 용 :
A granular material flow is a form of two-phase flow consisting of particulates and an interstitial fluid. When sheared the particulates may either flow in a manner similar to a fluid, or resist the shearing like a solid. The dual nature of these types of flows makes them difficult to analyze. Many research activities on granular flows are generally focused on computer simulation and/or analytical approaches. On the other hand, little experimental work is in progress due to lack of reliable instrumentation to measure precisely the velocity, solid fraction and velocity fluctuations of the flows. However, reasonable experimental measurements are essential to provide further underrstanding of granular flow characteristics.
In this seminar, after briefly presenting the speaker’s current research interests such as nanofluids, an artificial heart pump, fluid transients and a dryer system, he will discuss (1) general characteristics of granular flows, (2) shear flows, (3) granular flows through orifices, and (4) heat transfer to granular flows. His experimental and analytical methods along with his computer simulation will also be presented.

6. 연사약력 :
Hojin Ahn entered Seoul National University in 1980 and subsequently Mechanical Engineering Department in 1981. While in the second year, he moved to USA. He obtained all degrees from California Institute of Technology (Caltech): B.S. (1985), M.S. (1986) and Ph.D. (1989) in mechanical engineering. His undergraduate research at Jet Propulsion Laboratory covered drag reduction and heat transfer with non-Newtonian fluid such as polymer additives and clay suspension. Academically, he received the Henry Ford II Scholar Award which is awarded to a student with the best G.P.A. at Caltech at the end of the third year of undergraduate study. His graduate research work at Caltech focused on channel flow of particulate two-phase flow. Shear flow and convective heat transfer of granular materials were experimentally and analytically investigated. After graduation he worked at The Aerospace Corporation for 7 years. His main duty was to conduct various analyses of transient flows in liquid rocket engines and satellite propulsion systems which often involve two-phase flows and cryogenic propellants. He received the Group Achievement Award which is one of a few prestigious awards given by The Aerospace
Corporation. After moving to Turkey in 1996 with his family, he taught at Marmara University in Istanbul as a full-time staff for 8 years. Currently he is an associate professor at Yeditepe University in Istanbul. He has both American and Turkish citizenships.

7. 문 의 : 기계항공공학부 유정열 교수(☏ 880-7112)