正四角斷面덕트의 入口領域에서 亂流非正常流動의 流動特性에 關한 數植解析 = Nemerical analysis on flow characteristics of turbulent unsteady flows in the entrance region of a square duct

다국어 초록 (Multilingual Abstract)

The flow characteristics of turbulent pulsating flows are investigated numerically in the entrance region of a square duct (40 mm × 40 mm and 4,000 mm). The numerical analysis are incorporated by finite-volume discretization with staggered grid system and SIMPLE algorithm.
The numerical solution are compared with experimental results of mean velocity profiles, turbulence intensity, pressure distribution, shear stress distribution and entrance length.
Time-averaged velocity profiles of the turbulent pulsating flows follow the one-seventh power law profile in the fully developed flow region.
Turbulence intensity increases as the dimensionless transverse position increases from the center to the wall of the duct, and is slightly smaller in the accelerating phase than in the decelerating phase for the turbulent pulsating flows.
Shear stress distribution show maxmun when angular frequency is about 3 and minimum when angular frequency is about 0.
The entrance length of the turbulent pulsating flow is about 40 times as large as the hydraulic diameter under the present numerical solution.

목차 (Table of Contents)

• 목차 = Ⅰ
• List of Figures = Ⅲ
• Lisf of Tables = Ⅳ
• ABSTRACT = Ⅴ
• 제1장 서론 = 1
• 1.1 연구목적 = 1
• 1.2 연구배경 = 2
• 제2장 이론해석 = 5
• 2.1 지배방정식 = 5
• 2.2 난류모형 = 11
• 2.3 저레이놀즈수 난류모형 = 12
• 제3장 수치해석 = 14
• 3.1 유한차분 격자 = 14
• 3.2 지배방정식의 차분화 = 18
• 3.3 입구 및 경계조건 = 20
• 3.4 수렴조건 = 21
• 3.5 해법과정 = 21
• 3.6 안정성 = 24
• 제4장 결과 및 고찰 = 25
• 4.1 속도분포와 난류특성 = 25
• 4.2 압력분포 = 27
• 4.3 전단응력분포 = 28
• 4.4 입구길이 = 28
• 제5장 결론 = 47
• 參考文獻 = 48