Aerodynamic Study of Go-kart Nose Cones ME450 Introduction to Computer Aided Engineering Becker, Joe Professor H. U. Akay May 1, 2000

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

Project Objective Use Finite Element Code (ANSYS: CFD component FLOTRAN) for the following 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

Theory: Assumptions Steady State Steady State Newtonian Fluid Newtonian Fluid No-slip at Fluid\Solid Interface No-slip at Fluid\Solid Interface Turbulent Turbulent Incompressible Incompressible Isothermal Isothermal

Model Setup: Basic Geometry Figure 1: Shape 1 in Flow Field Figure 2: Shape 2 in Flow Field

Basic Geometry Comparison

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

Shape 1: Areas

Shape 2: Areas

Mapped Meshes Shape 1 Mapped Mesh Shape 2 Mapped Mesh

Free Meshes Shape 1 Free Mesh Shape 2 Free Mesh

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

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

Results

Shape 1 Velocity (m/s)

Shape 2 Velocity (m/s)

Shape 1 Pressure (Pa)

Shape 2 Pressure (Pa)

Shape 1 Turbulent KE (J)

Shape 2 Turbulent KE (J)

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

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

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

I AM DONE!