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Document Type |
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Thesis |
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Document Title |
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ON THE DEVELOPMENT OF LAMINAR SEPARATION BUBBLE AT LOW REYNOLDS NUMBER دراسة خصائص فقاعة الانفصال الصفائحية عند أعداد رينولدز منخفضة |
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Subject |
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Faculty of Engineering |
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Document Language |
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Arabic |
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Abstract |
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In low Reynolds number flows laminar separation occurs before transitioning to turbulent boundary layer, forming laminar separation bubble (LSB). When encountered on airfoils; LSB leads to nonlinearity in the aerodynamic characteristics, and it adversely affects airfoil aerodynamic performance such as increase in drag and decrease in lift. In this study, the effect of low Reynolds numbers on the flow around an airfoil is carried out to resolve some of the flow features causing the nonlinearity in airfoil aerodynamic characteristics. Toward this goal, a study of different solution-approaches/turbulence-models was carried out to assess their performance in predicting the aerodynamic characteristics of airfoils at low Reynolds number. The steady and transient flow around NACA 0012 airfoil at angle of attack α = 5˚ and Re = 50,000 is computed using three turbulence models: GEKO, Transition-k-kl-ω and γ-Reθ SST-Transition. Comparison with experimental measurements shows that the optimal combination of solution-approach/turbulence-model is URANS (Unsteady RANS) using Transition-k-kl-ω model. The study on the effect of Reynolds number was then carried out at four Reynolds numbers Re = 30000, 50000, 70000 and 100000 at an angle of attack α = 0˚ to 5˚ with step size of 0.25˚. Analysis of streamline patterns, wall shear stress, and pressure gradient revealed a coupling behavior between the nonlinearity in lift coefficient and the characteristics of the separation bubble including its length, height, and location.
Key words: Low Reynolds Number, Laminar Separation Bubble, NACA 0012, RANS, Nonlinear Aerodynamics |
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Supervisor |
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Dr. Ibraheem AlQadi |
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Thesis Type |
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Master Thesis |
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Publishing Year |
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1445 AH
2023 AD |
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Added Date |
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Friday, November 10, 2023 |
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Researchers
| محمد فهد خان | Khan, Mohammed Fahad | Researcher | Master | |
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