Aerodynamic Study of Gokart Nose Cones

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Aerodynamic Study ofGo-kart Nose Cones

• ME450 Introduction to Computer Aided Engineering
• Becker, Joe
• Professor H. U. Akay
• May 1, 2000

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Example of Enduro Type Go-kart

• Driver lays on his\her back
• Race on road courses such as Mid-Ohio
• Speeds are in excess of 80 mph (35.76 m/s)

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Project Objective

• Use Finite Element Code (ANSYS CFD component
  FLOTRAN) for the following
• Comparison of two nose cone shapes to determine
  which is more aerodynamic
• Comparison of two meshing techniques
• Mapped Mesh (Structured Mesh)
• Free Mesh

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Theory Assumptions

• Steady State
• Newtonian Fluid
• No-slip at Fluid\Solid Interface
• Turbulent
• Incompressible
• Isothermal

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Model Setup Basic Geometry
Figure 1 Shape 1 in Flow Field
Figure 2 Shape 2 in Flow Field
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Basic Geometry Comparison
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ANSYS Procedure

• Define Keypoints and Create Lines
• Make Areas from Line Loops
• Mesh Areas
• Set Boundary Conditions
• Set Solver Parameters
• Solve FLOTRAN

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Shape 1 Areas
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Shape 2 Areas
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Mapped Meshes
Shape 1 Mapped Mesh
Shape 2 Mapped Mesh
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Free Meshes
Shape 1 Free Mesh
Shape 2 Free Mesh
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Boundary Conditions

• All Boundary Conditions were applied to lines
• Velocity of 0 m/s applied to ground and all
  surfaces of kart
• Velocity of 35.76 m/s in x-direction applied to
  the upper free stream surface
• Relative Pressure of 0 Pa applied to outlet

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FLOTRAN Parameters

• Steady-state with turbulent solver
• Fluid properties set to air in standard SI
• Solver set to perform 250 iterations

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Results
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Shape 1 Velocity (m/s)
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Shape 2 Velocity (m/s)
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Shape 1 Pressure (Pa)
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Shape 2 Pressure (Pa)
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Shape 1 Turbulent KE (J)
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Shape 2 Turbulent KE (J)
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Shape 1 Free Mesh Results
Shape 1 Velocity (m/s)
Shape 1 Pressure (Pa)
Shape 1 Turbulent KE (J)
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Shape 2 Free Mesh Results
Shape 2 Velocity (m/s)
Shape 2 Pressure (Pa)
Shape 2 Turbulent KE (J)
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Conclusion

• Shape 1 is better than Shape 2
• A mapped mesh is slightly better than a free mesh
• Results are only as good as the mesh that they
  arise from

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I AM DONE!