1. 2D flow past an airfoil with different angles of attack Submitted to Submitted by - Dr Harish Dixit -Apurva Bhagat(me13m1026) -Harshal Gijare (me13m1028) -Rahul Devnagare(me13p1008)

2. Introduction to problem AIM:-To use CFD as a tool to illustrate the concept of separation and how the airfoil angle of attack affects the flow. Parameters Varied 1. Reynolds Number 2. Angle of attack 3. Mesh Details ICEM-CFD is used to prepare a Mesh Quadrilateral cells are used because they can be streched easily to account for different flow gradients in different directions Mesh is more fine (High aspect ratio) near the airfoil surface. Parabola is choosen for far field boundary it has no discontinuties in slope. .msh file is generated and imported to openFoam No of cells-9800. 4. Solver Details IcoFoam-Incompressible solver is used. Incompressible N-S equations are used for discretization in this solver. Finite Volume Method is used for discretization. Euler scheme is used for time steping and Gauss linear scheme is used for Pressure and velocity solution. Courant no < 0.5 5. Cases Studied. Kinematic Viscosity is fixed = 0.01 Flow over aerofoil is observed at different angles of attack 1 degree to 15 degree at fixed reynolds number Re=500. Flow seperation is observed. Reynolds number is varied by changing free stream velocity. Re=100 to Re=20000 6. Velocity Contours at different angle of attack (Re=500) Alpha = 1 Alpha = 7 Alpha = 15 Alpha = 11 7. Velocity contours at Re=500,angle of attack = 1 8. Velocity contours at Re=500,angle of attack = 3 9. Velocity contours at Re=500,angle of attack = 5 10. Velocity contours at Re=500,angle of attack = 7 11. Velocity contours at Re=500,angle of attack = 9 12. Velocity contours at Re=500,angle of attack = 11 13. Velocity contours at Re=500,angle of attack = 13 14. Velocity contours at Re=500,angle of attack = 15 15. Pressure variation w.r.t angle of attack Angle of attack = 3 Angle of attack = 7 Angle of attack = 15 Angle of attack = 11 16. Lift & Drag coefficients w.r.t. angle of attack Typical Aerofoil Lift & Drag Curve Lift & Drag curve of Aerofoil under study 17. Velocity contours at Re=100,angle of attack = 5 18. Velocity contours at Re=500,angle of attack = 5 19. Velocity contours at Re=1000,angle of attack = 5 20. Velocity contours at Re=5000,angle of attack = 5 21. Velocity contours at Re=10000,angle of attack = 5 22. Velocity contours at Re=20000,angle of attack = 5 23. Behaviour of flow w.r.t Reynolds no. (Velocity contours) Re=100 Re = 500 Re =1000 Re = 20000 Re = 10000 Re = 5000 24. Variation of coefficient of drag w.r.t. Re 25. Conclusion Reynolds number has no effect on the laminar separation point. Increasing Reynolds number can cause a transition to turbulent boundary layer ahead of separation and effectively move the separation point downstream. Coefficient of lift increases as angle of attack increases (till stall angle) at fixed Reynold no. Coefficient of drag increases as angle of attack increases (at fixed Re). Pressure drag dominates friction drag as angle of attack increases (at fixed Re). Coefficient of drag decreases as Re increases (at fixed angle of attack) 26. Thank You!