Ludwieg Tube의 작동특성에 관한 수치해석적 연구 = A Computational Study on the Operation Characteristics of Ludwieg Tube

다국어 초록 (Multilingual Abstract)

Among the many different types of wind tunnels, Ludwieg Tube(LT) is the most suitable facility for high Reynolds number testing. Depending on the location of diaphragm, there are two types of LTs. In the present study, a computational work has been carried out to compare the operation characteristics of upstream- and downstream-diaphragm LTs. Two- dimensional, axisymmetric, unsteady, compressible Navier-Stokes equations were solved using a fully implicit finite volume scheme. Based on the present results, the flow mechanism of the starting process was discussed in detail using wave diagrams and characteristics of starting time and working time were investigated.

목차 (Table of Contents)

• 제 1 장 서 론 1
• 1.1 연구배경 1
• 1.2 종래의 연구 6
• 1.3 연구목표 10
• 제 2 장 Ludwieg Tube 11
• 2.1 Ludwieg Tube 작동원리 11
• 2.2 비정상 압축성 이론해석 16
• 2.3 각종 Ludwieg Tube 21
• 2.3.1 하류막 Ludwieg Tube 21
• 2.3.2 상류막 Ludwieg Tube 22
• 2.3.3 기타 Ludwieg Tube 23
• 제 3 장 수치해석법 24
• 3.1 Ludwieg Tube 형상 24
• 3.2 계산영역 및 경계조건 25
• 제 4 장 결과 및 고찰 28
• 4.1 하류막 Ludwieg Tube의 수치해석 결과 28
• 4.1.1 시동과정과 유동특성 28
• 4.1.2 시동시간 및 작동시간 30
• 4.2 상류막 Ludwieg Tube의 수치해석 결과 37
• 4.2.1 시동과정과 유동특성 37
• 4.2.2 시동시간 및 작동시간 37
• 4.3 하류막 방식과 상류막 방식의 비교 39
• 4.4 작동시간의 연장에 대한 고찰 44
• 제 5 장 결론 46
• 참고문헌 47
• Abstract 50
• 감사의 글 51
• 석사과정 중 발표논문 53
• 그림 및 표 목록
• Figure 1. Reynolds number of wind tunnel and real flights 4
• Figure 2. Comparison of pressure distributions on airfoil 5
• Figure 3. Typical wave diagram of simple shock tube 9
• Figure 4. Typical Ludwieg tube and wave diagram 13
• Figure 5. Characteristic properties at entrance of reservoir tube 20
• Figure 6. Characteristic properties at test section 20
• Figure 7. Ludwieg tube configurations 26
• Figure 8. Computational grid and boundary conditions 26
• Figure 9. Predicted pressure history at measuring point S1 of DDLT (p41=50) 27
• Figure 10. Comparison of experimental and computational pressure history at measuring point S1 of DDLT (p41=50) 31
• Figure 11. Comparison of experimental and computational pressure history at measuring point T of DDLT (p41=50) 32
• Figure 12. Predicted pressure history at measuring point S1 of DDLT 33
• Figure 13. Relation between starting time(ts) of steady flow and Mach number in reservoir tube 34
• Figure 14. Wave diagram for the starting process based on the computational results (p41=30, 70) 35
• Figure 15. Predicted pressure history at measuring point S1 of UDLT 38
• Figure 16. Wave diagram of the starting process based on the computational results (DDLT, p41=50) 41
• Figure 17. Wave diagram of the starting process based on the computational results (UDLT, p41=50) 42
• Figure 18. Comparison of the working time(tw) and the starting time(ts) at measuring point S1 of both LTs 43
• Table 1. Characteristics of DDLT & UDLT 15