Bridging Simulation and Competition: A Systematic CFD Analysis of Aerodynamic Performance in CO₂-Powered Dragsters

This study presents a comprehensive aerodynamic analysis of a CO₂-powered dragster using high-fidelity computational fluid dynamics (CFD). The research focuses on establishing a robust and accurate simulation methodology to guide design optimization for competitive racing. Key parameters including computational domain sizing, mesh refinement strategy, and the implementation of realistic boundary conditions such as wheel rotation and a moving ground plane are systematically investigated. The analysis identifies and examines critical aerodynamic phenomena, including the formation of dominant twin vortex structures in the vehicle's wake, extensive wake turbulence, and the pressure distributions driving drag. A baseline simulation using coarse settings and non-rotating wheels yielded a total drag of -0.085 N, highlighting a significant underprediction of aerodynamic load. By systematically refining the methodology—implementing a finer mesh (Level 5), rotating wheels, and optimizing the computational floor length—the simulation's predictive accuracy was vastly improved. The final optimized design configuration achieved a total drag force of -0.132 N at a peak velocity of 28 m/s. While this represents a 22% aerodynamic improvement over initial refined concepts (-0.169 N), it remains higher than the 0.06–0.08 N drag forces reported for national championship-winning designs, indicating specific areas for further optimization. The paper concludes by providing a component-level drag breakdown and offering a framework for future design enhancements and advanced simulation work.