The wavy fins have been widely used in the heat exchangers in coolering system, aerospace system and automotive. Especially, an automobile has the wavy fin and flat tube heat exchanger for oil cooling system. The objective of this research is the performance comparison of wavy fins for battle vehicle diesel engine oil-cooler by numerical analysis. The real type fin is the wavy fin with corrugated structure, and the comparative fin surfaces are plain, louver, lateral perforation and parallel wavy fin. The non-dimensional values of f-factor, j-factor, area goodness factor and volume goodness factor was performed on the performance comparison. The plain and louver fin shows the highest performance in pressure drop and heat transfer respectively. In the area goodness factor and volume goodness factor results, the parallel wavy fin and louver fin show the highest values at each result.

The wavy fins have been widely used on the compact heat exchangers in aero system, automotive, air-conditioner and cooler system. The Special Purpose Vehicle has many oil used system and it need cooling system by air in form of fin-flat tube heat exchanger. The objective of this work is to evaluate the performance of wavy fin by Computational Fluid Dynamics(CFD) analysis. 3 modified models were suggested to change protrude direction or to remove blocked surface bot and top of corrugated fin. The base model shows the lowest performance in pressure drop, and modified model 3 shows the highest performance in heat transfer rate. But, modified model 2 has the highest value in the Area goodness factor results, and modified model 3 has the highest value in the Volume goodness factor results.

지난 2005년 1월 4일 보현산 천문대(BOAO)의 BOES(BOao Echelle Spectograph)를 이용하여 Machholz(C/2004Q2) 혜성을 관측하였다. 이 논문에서는 Machholz 혜성의 고분산 분광 자료를 이용하여 미확인 분광선에 관한 연구를 수행하였으며 연구에 이용된 분광선의 파장 범위는 4800 ~ 8100A 영역이다. 기존에 있던 Swift-Tuttle 혜성 Brosen-Metcalf 혜성, Austin 혜성, 그리고 122P/de Vico 혜성의 자료들과 비교분석을 하였다. 다수의 미확인 분광선에 대한 원인물질을 알아냈고, 이러한 자료들은 앞으로 혜성 연구에 있어서 유용한 자료로 활용될 수 있을 것이다.