Automotive Aerodynamics Optimization
Reducing Drag for High-Performance Electric Vehicle
Velocity (m/s): 0 → 60
Velocity magnitude field showing optimized underbody flow with reduced separation zones
Abstract
A leading automotive manufacturer approached us to optimize the aerodynamic performance of their new electric sports car platform. The primary objective was to reduce drag coefficient while maintaining adequate downforce for high-speed stability.
Our CFD analysis identified critical flow separation zones in the underbody region and rear diffuser. Through iterative optimization using RANS simulations with k-omega SST turbulence modeling, we developed a refined underbody geometry featuring optimized diffuser angles and strategic vortex generators.
The final design achieved a 23% reduction in drag coefficient while improving rear downforce by 15%. Wind tunnel validation confirmed CFD predictions within 3% accuracy. The improvements translated to an estimated 8% increase in vehicle range at highway speeds.
Metodologia
Numerical Approach
- ▸Incompressible steady-state RANS simulation with k-ω SST turbulence model
- ▸Second-order upwind discretization for momentum and turbulence equations
- ▸SIMPLE algorithm for pressure-velocity coupling
- ▸y+ < 1 wall treatment with enhanced wall functions
- ▸Convergence criteria: residuals < 1e-5, force monitors stabilized
Computational Domain
- ▸Full-scale vehicle geometry with rotating wheels
- ▸Domain size: 10L upstream, 20L downstream, 5L lateral, 5L vertical
- ▸Hexahedral-dominant mesh with prism layers near walls
- ▸15 prism layers with expansion ratio 1.2
- ▸Local refinement zones around mirrors, wheels, and underbody
- ▸Inlet: uniform velocity 40 m/s (144 km/h)
- ▸Outlet: zero gradient pressure
- ▸Ground: moving wall matching freestream velocity
Risultati e Scoperte
The optimized configuration achieved all performance targets while maintaining aesthetic design requirements.
Key Findings
- 1Primary drag contribution from underbody (38%) and rear base (29%)
- 2Optimized diffuser angle reduced wake turbulence by 34%
- 3Vortex generators improved rear downforce without drag penalty
- 4Total Cd reduced from 0.31 to 0.24
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