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Analysis of Flow Separation Over Aerodynamic Airfoils

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Analysis of Flow Separation Over Aerodynamic Airfoils ANALYSIS OF FLOW SEPARATION OVER AERODYNAMIC AIRFOILS Sergio Jesús Rodríguez Sánchez October, 2014 UNIVERSIDAD CARLOS III DE MADRID ESCUELA POLITÉCNICA SUPERIOR BACHELOR THESIS Aerospace Engineering Tutor: Óscar Flores Arias 1 Contents 1 Introduction 7 1.1 Motivation . 7 1.2 Wind turbines . 10 1.2.1 Eolic Energy . 10 1.2.2 Wind turbines review . 11 1.2.3 Wind turbines parameters of study . 14 1.3 Air ow over 2D airfoils . 15 1.4 Boundary Layer . 18 1.4.1 Boundary layer description . 18 1.4.2 Equations governing boundary layer behavior . 19 1.4.3 Separation point . 19 1.4.4 Relevance of separation in airfoil optimization . 19 1.5 Tubulence . 20 1.5.1 Turbulence review . 20 1.5.2 Turbulence models brief description and selection criteria . 21 1.5.3 Turbulent ows eect on wind turbines . 22 2 Objectives 23 2.1 Goals . 23 2.2 Optimization method . 23 3 Methodology 24 3.1 Prole . 24 3.1.1 Selection Rationale . 24 3.1.2 Prole description . 24 3.1.3 Prole mesh . 24 3.1.4 Mesh validation . 30 3.2 XFLR5 . 31 3.2.1 Description . 31 3.2.2 Operations with XFLR5 . 32 3.3 OpenFoam . 32 3.3.1 Description . 32 3.3.2 Why OpenFoam? . 33 3.3.3 Operations with OpenFoam . 33 4 Software 34 4.1 XFLR5 . 34 4.1.1 Case setup . 34 4.1.2 Objectives . 41 4.2 OpenFoam . 41 4.2.1 Case setup . 41 4.2.2 Objectives . 46 5 Results 46 5.1 XFLR5 outputs . 46 5.2 OpenFoam outputs . 51 5.3 Optimization method . 53 5.3.1 Scenario 1 . 54 2 5.3.2 Scenario 2 . 55 5.4 Final results . 56 6 Conclusions 63 6.1 Software Validation and Advantages . 63 6.2 Improvement on boundary layer separation . 64 6.3 Economic impact estimation . 64 6.4 Next steps . 64 7 Appendix I. Software input data les 65 7.1 XFLR5 airfoil input data le . 65 7.2 OpenFoam airfoil input data le . 66 8 Appendix II: OpenFoam Tutorial 66 8.1 What is OpenFoam? . 66 8.2 How to install OpenFoam on your computer? . 67 8.3 How to run a case using OpenFoam? . 67 8.4 Solver selection . 67 8.5 Files used in the set-up of an OpenFoam case . 68 8.6 Post-processing: results' les and ParaFoam . 69 References 71 3 List of Figures 1 Eolic resources in the European Region . 7 2 Electric Power Generation. Aug. 30th, 2014. 8 3 Wind turbine blade vs. Aircraft wing. Images for the comparison are obtained from [1] and [2]. 12 4 Horizontal Axis Wind Turbine . 12 5 Drag-Type (Persian) Wind Turbine . 13 6 Lift-Type Wind Turbine . 13 7 Magnus Wind Turbine . 14 8 Vortex Wind Turbine . 14 9 Wing/blade Aspect Ratio . 15 10 Lift and Drag forces . 16 11 S809 polar . 17 12 Flow over 2D airfoil . 18 13 Boundary layer thickness . 18 14 NREL's S809 airfoil prole . 24 15 S809 airfoil in XFLR5 . 25 16 Gmsh graphic interface . 25 17 Airfoil prole mesh . 26 18 Mesh Contour denition . 27 19 Mesh Surfaces . 28 20 Final Mesh . 28 21 Mesh Airfoil Detail . 29 22 Mesh Leading Edge Detail . 29 23 Mesh Trailing Edge Detail . 30 24 Original Mesh Scenario 2 . 30 25 Rened Mesh Scenario 2 . 31 26 Opening project XFLR5 . 34 27 Loading S809 data le . 34 28 Direct Analysis for airfoil S809 . 35 29 XFLR5 direct analysis control panel . 35 30 Batch Analysis selection . 36 31 Batch Analyis type selection . 36 32 Graphic results for XFLR5 analysis . 37 33 Pressure distribution XFLR5 . 37 34 Inverse Analysis selection . 38 35 Inverse Analysis Original Airofoil . 38 36 New Spline . 39 37 Optimization Region Selection . 39 38 New airfoil . 40 39 Storing new prole . 40 40 Prole Renement . 40 41 cl vs a comparison . ..
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