Computational fluid dynamics based optimisation of emergency response vehicles

Formal optimisation studies of the aerodynamic design of Emergency Response Vehicles, typically encountered within the United Kingdom, were undertaken. The objectives of the study were to optimise the aerodynamics of the Emergency Response Vehicles such as Ambulance and Police cars, in terms of drag force.
A combination of wind tunnel tests and the Computational Fluid Dynamics (CFD) simulations were used to analyse the flow field and aerodynamic characteristics of Emergency Response Vehicles. The experimental data were used to validate the computer simulations and the good agreement observed gave confidence in the results obtained. Results from computer simulations on the scale models and full-scale models, were also characteristically similar to those of the validated scale model.
Computational Fluid Dynamics (CFD) was combined with an efficient optimisation framework to minimize the drag force of three different types of Emergency Response Vehicles, Ambulance Van Conversion, Police Van Conversion and Police Sedan car Conversion. The benefits of employing an airfoil-based roof design and Bezier curve fitting approach which minimizes the deleterious aerodynamic effects of the required front and rear light-bars, were investigated. Optimal Latin Hypercube (OLH) Design of Experiments, the Multipoint Approximation Method (MAM) and surrogate modelling were used for the optimisation.
Optimisation results demonstrated a clear improvement of the aerodynamic design of the Emergency Response Vehicles named above. It was also clearly demonstrated that improving the aerodynamic design of Emergency Response Vehicles roof offers a significant opportunity for reducing the fuel consumption and emissions for Emergency Response Vehicles.