在本文中，我們選擇了 Bauhaus Luftfahrt 開發的 Ce-Liner 飛機作為我們的研究對象，該飛機採用 C-wing設計。該C-wing設組件基於非平面的三面配置：主翼、側翼和頂翼。本論文採用ANSYS FLUENT來模擬該飛機在巡航過程中能否減少翼尖渦的產生和強度，以及能否提高飛機的效率並獲得更好的經濟效益。
首先需要驗證 DLF-F6 模型，當前數值結果與實驗值相比以確保了我們方法的正確性。因此，將在整個 Ce-Liner 上實施相同的數值方法和網格生成技術，可以發現這種C-wing設設計由於減少了翼尖渦流而具有非常顯著的空氣動力學優勢。我們的 Ce-Liner 配置可以將巡航期間的升阻效率提高約 20%。由於這架Ce-Liner是全電動飛機，它可以大大減輕渦扇發動機和燃油的重量，從而可以取消高升力裝置，進一步降低機翼的機械複雜性和生產或維護成本。此外，這種Ce-Liner不需要在主翼上儲存燃料，因此可以進一步減少機翼的厚度和重量。此外，由於我們的陣風側風模擬，發現這種飛機配置具有更強的抗側風能力。因此，我們的研究確實證明了歐盟項目 Flightpath 2050 的要求，並確認這種 Ce-Liner 配置可以為未來環境更清潔的天空做出貢獻。

In this work, the Ce-Liner aircraft developed by Bauhaus Luftfahrt is selected as our research target, and the aircraft has a C-wing design. This C-wing assembly is based on a non-planar three-surface configuration: the main wing, side wing and top wing. This work implement ANSYS FLUENT to simulate whether this aircraft can reduce the generation and strength of wingtip vortices during cruise, and whether it can improve the efficiency of the aircraft with better economic benefits.
The DLF-F6 model need to be validate first, and current numerical results compared with experimental values seems ensure the correctness of our approach. Consequently, the same numerical method and grid generation technique will be implemented for the overall Ce-Liner, and it can be found that this C-wing design has a very significant aerodynamic benefit due to the reduction of wingtip vortices. Our Ce-Liner configuration can increase the lift-to-drag efficiency by about 20 percent during cruise. Because this Ce-Liner is an all-electric aircraft, it can greatly reduce the weights of the turbofan engine and fuel, thus the high-lift devices can be eliminated, which could further reduce the mechanical complexity of the wing and the production or maintenance cost. Furthermore, this Ce-Liner will not need to stock fuel in the main wing, hence the thickness and weight of the wing could be further reduced. In addition, it is found that this aircraft configuration has a stronger crosswind resistance capability due to our gust crosswind simulation. Thus our research indeed justifies the requirements of the European Union project Flightpath 2050, and confirm that this Ce-Liner configuration can contribute to the cleaner sky for future environment.

Contents
Abstract	V
Contents	VII
List of Figures	IX
List of Tables	XIV
List of Symbols	XV
Chapter 1 Introduction	1
Chapter 2 Research Background	5
2.1 Feasibility of All-Electric Passenger Aircraft	6
2.2 Wingtip Vortices	7
2.3 Winglet	8
2.4 Non-Planar Wing	10
2.5 C-wing	12
2.6 Computational Fluid Dynamics	14
2.7 Gust Wind Model	15
Chapter 3 Numerical Modeling	18
3.1 Geometry Model Construction	18
3.2 Mesh and Boundary Conditions	23
3.3 Governing Equations and Flow Solver	26
3.4 Numerical Setup	28
3.5 Turbulence Model	29
Chapter 4 Validation	32
4.1 DLR-F6 Model	32
4.2 Grid Convergence	43
Chapter 5 Results and Discussion	46
5.1 Ce-Liner Flight Parameters Analysis	46
5.2 Ce-Liner Aerodynamic Analysis during Cruise	51
5.3 Ce-Liner Aerodynamic Analysis at Higher AoA Degrees	60
5.4 Crosswind Simulation Results	73
Chapter 6 Conclusion	81
References	84

List of Figures
Figure 1 Bauhaus Luftfahrt Ce-Liner design ……………………………..1
Figure 2 Bauhaus Luftfahrt Ce-Liner three-view ………………………...5
Figure 3 Wingtip vortices with and without winglet………………………8
Figure 4 Winglet of Airbus A350-941……………………………..……10
Figure 5 Span efficiency factor (e) for non-planar wing planforms …….11
Figure 6 Nonplanar wings: results for the optimal aerodynamic efficiency ratio ε ……………………………..……………………………………..12
Figure 7 Non-planar C-wing layout …………………………………….13
Figure 8 Geometry of Ce-Liner………………………………………….17
Figure 9 NASA SC (2)-0710 ……………………………………………19
Figure 10 NACA 0010 ………………………………………………….19
Figure 11 Airfoil of main wing …………………………………………19
Figure 12 Top view of Ce-Liner…………………………………………21
Figure 13 Front view of Ce-Liner………………………………………..22
Figure 14 Left view of Ce-Liner…………………………………………22
Figure 15 Ce-Liner boundary conditions and domain size ……………..24
Figure 16 Engine boundary conditions ………………………………….24
Figure 17 Mesh of whole Ce-Liner domain …………………………….25
Figure 18 Mesh of sliced main wing ……………………………………25
Figure 19 DLR-F6 Wing-Body geometry ………………………………33
Figure 20 Mesh of DLR-F6 ……………………………………………..34
Figure 21 Mesh of whole DLR-F6 domain ……………………………..34
Figure 22 DLR-F6 boundary condition and domain size ……………….35
Figure 23 DLR-F6 wing body pressure contour at different wing sections………………………………………………………………….35
Figure 24 (a-h) Pressure distribution comparisons for the wing-body configuration at 8 span-wise locations: (a) 15%, (b) 23.9%, (c) 33.1%, (d) 37.7%, (e) 41.1%, (f) 51.4%, (g) 63.8%, (h) 84.7% ……………………39
Figure 25 DLR-F6 contour of vorticity………………………………….41
Figure 26 DLR-F6 vortex with Q-criterion, Q=2000 1/s^2……………..41
Figure 27 DLR-F6 contour of turbulence intensity ……………………..42
Figure 28 Ce-Liner lift coefficient C_L vs. cell numbers ………………..43
Figure 29 Ce-Liner lift coefficient C_D vs. cell numbers ……………….44
Figure 30 Ce-Liner C_L vs. AoA ..………………………………….…..48
Figure 31 Ce-Liner C_D vs. AoA ..………..…………………........……48
Figure 32 Ce-Liner C_m vs. AoA ..…………………….……….………49
Figure 33 Ce-Liner lift-to-drag ratio vs. AoA ..….……………………..49
Figure 34 Lift coefficient composition chart of each part during cruise..51
Figure 35 Drag coefficient composition chart of each part during cruise …………………………………………………………………....51
Figure 36 Ce-Liner velocity contour plot during cruise, side view……..52
Figure 37 Ce-Liner pressure contour plot during cruise, side view ……53
Figure 38 Ce-Liner surface pressure contour plot during cruise, top view…………………………………………………………………..….54
Figure 39 Ce-Liner surface pressure contour plot during cruise, below view ……………………………………………………………………..54
Figure 40 Velocity contour plot at MAC location during cruise ……….55
Figure 41 Pressure contour plot of MAC location during cruise ………56
Figure 42 Ce-Liner surface vorticity contour plot during cruise, top view …………………………………………………………………….57
Figure 43 Ce-Liner surface turbulence intensity contour plot during cruise, top view …………………………………………………………57
Figure 44 Ce-Liner surface turbulence kinetic energy contour plot, during cruise top view ………………………………………………………….58
Figure 45 Ce-Liner Q-criterion distribution plot during cruise, Q=2000 1/s^2 ……………………………………………………………………58
Figure 46 Ce-Liner turbulence viscosity distribution plot during cruise ……………………………………………………………………59
Figure 47 Lift coefficient composition chart of each part at 6 degree AoA …………………………………………………………………..…61
Figure 48 Drag coefficient composition chart of each part at 6 degree AoA ……………………………………………………………………..61
Figure 49 Ce-Liner surface pressure contour plot at 6 degree AoA, top view ……………………………………………………………….…….62
Figure 50 Velocity contour plot of MAC location at 6 degree AoA …....63
Figure 51 Pressure contour plot of MAC location at 2 degree AoA …....63
Figure 52 Ce-Liner surface vorticity contour plot at 6 degree AoA ...….64
Figure 53 Ce-Liner Q-criterion distributed at 6 degree AoA, Q=2000 1/s^2 ………………………………………………………………….....65
Figure 54 Ce-Liner surface pressure contour plot at 11 degree AoA, top view ……………………………………………………………………..66
Figure 55 Ce-Liner surface pressure contour plot at 12 degree AoA, top view …………………………………………………………………….66
Figure 56 Velocity contour plot of MAC location at 11 degree AoA ….67
Figure 57 Velocity contour plot of MAC location at 12 degree AoA ….68
Figure 58 Pressure contour plot of MAC location at 11 degree AoA ….68
Figure 59 Pressure contour plot of MAC location at 12 degree AoA ….69
Figure 60 Ce-Liner Q-criterion distribution plot at 11 degree AoA, Q=2000 1/s^2 ………………………………………………………….70
Figure 61 Ce-Liner Q-criterion distribution plot at 12 degree AoA, Q=2000 1/s^2 ………………………………………………………….70
Figure 62 Vorticity contours around the Ce-Liner by various planes with levels cutoff below 2 1/s during cruise………………………………….71
Figure 63 Vorticity contours around the Ce-Liner by various planes with levels cutoff below 2 1/s at 12 degree AoA …………………………….72
Figure 64 Ce-Liner surface pressure contour plot in crosswind ………..74
Figure 65 Ce-Liner surface pressure contour plot without crosswind, top view …………………………………………………………………….74
Figure 66 Ce-Liner surface pressure contour plot in 20 m/s crosswind, top view …………………………………………………………………….75
Figure 67 Velocity contour plot of right MAC location in 20 m/s crosswind ……………………………………………………………….76
Figure 68 Pressure contour plot of right MAC location in 20 m/s crosswind ……………………………………………………………….76
Figure 69 Ce-Liner surface vorticity contour plot in 20 m/s crosswind ..77
Figure 70 Ce-Liner surface vorticity contour plot in 20 m/s crosswind, top view ..…………………………………………………………………...78
Figure 71 Ce-Liner surface turbulence kinetic energy contour plot in 20 m/s crosswind, top view …………………………………………………….78
Figure 72 Ce-Liner Q-criterion distribution in 20 m/s crosswind, Q=2000 1/s^2 …………………………………………………………...……….79
Figure 73 Rolling moment coefficient Cl vs. time response under 20 m/s gust crosswind ……………………………………………………80

List of Tables
Table 1 The dCl/dβ value of B747-200 ……………………………………17
Table 2 Ce-Liner configuration parameters …………………………….21
Table 3 Parameters of flight in cruise at FL 280 ………………………..29
Table 4 The C_L and C_D value in different grid number ………………45
Table 5 Parameters of performance for Ce-Liner cruising at FL 280 …..49
Table 6 The dCl/dβ value in each crosswind speed interval ………………80

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