School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Aerodynamic Design Optimization Harvey Thompson & Colleagues

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING - Importance of Aerodynamic Drag - Computational Fluid Dynamics (CFD) - Aerodynamic Design Optimization via CFD

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Importance of Aerodynamic Drag Aerodynamics is a crucial component of a vehicle’s energy efficiency E.g. ETSU (2001) Truck Aerodynamic Styling: over 1/3 of Heavy Goods Vehicles’ Fuel Burn related to aerodynamic drag

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Computational Fluid Dynamics (CFD) CFD – solving governing equations of heat and fluid flow on computers. Can provide ability to carry out ‘virtual experiments’. CFD increasingly important in vehicle design: E.g. US Department of Energy funded consortium (>$5 million) - best practice guidelines for CFD in truck design.

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Computational Fluid Dynamics (CFD) E.g. Flow past small livestock trailer (Ifor Williams) Recirculation Wake wake recirculation

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Computational Fluid Dynamics (CFD) Flow is highly turbulent – hence need to validate turbulence model predictions: flow in wake particularly challenging e.g. wind tunnel testing

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Aerodynamic Design Optimization via CFD Validated CFD models can be used to investigate benefits of design changes. E.g. effect of inlet on ventilation rate for animals.

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Aerodynamic Design Optimization via CFD More efficient to combine CFD with formal methods for multi-objective optimization. E.g. effect of headboard fairing on drag/ventilation Three possible Three resultant fairings design parameters

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Aerodynamic Design Optimization via CFD Use ‘Design of Experiments’ to minimize number of CFD calculations needed to generate a ‘response surface’ Small D1 Large D1

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Aerodynamic Design Optimization via CFD Use response surface to identify ‘best’ design subject to your multi-objective criteria. E.g. Identify minimum drag with acceptable ventilation rate for animals. Small D1 Large D1

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Aerodynamic Design Optimization via CFD Automatic parametrisation and optimization of aero engine compressor blade: ≈ 1% increase in adiabatic efficiency. Small D1 Large D1

School of Mechanical Engineering FACULTY OF ENGINEERING School of Mechanical Engineering FACULTY OF ENGINEERING Any Questions? Small D1 Large D1