Influence of Different Road Vehicle Positioning on The Aerodynamic and Aeroacoustics Characteristics Using CFD Analysis

Abstract

The rise in private vehicle ownership has led to more vehicles on the road, particularly during peak hours in highways and densely populated areas such as metropolitan and industrial regions. This situation results in increasing fuel consumption and environmental pollution. This study examines the influence of vehicle positioning and longitudinal spacings on aerodynamic and aeroacoustic characteristics using computational fluid dynamics (CFD) analysis. The research evaluates aerodynamic loads, flow patterns, pressure distribution, vortex generation, and surface acoustic power levels for cars and double-decker buses. A grid independence test ensures the accuracy of the simulations. Six configurations with longitudinal spacings of 4 and 8 meters are analyzed, focusing on the interaction of vehicles in different positions. The results show that the Bus-Car-Car configuration (Case E) with a 4-meter longitudinal space is the most effective way to minimize aerodynamic drag and enhance energy efficiency. In this configuration, the drag coefficient (Cd) for the bus is lowered to 0.671, while the trailing cars see significant reductions in their drag coefficients, reaching 0.148 and 0.246, respectively. Compared to other configurations, Case E achieves up to a 37% reduction in drag for the bus and a 50–60% reduction for the trailing vehicles. This setup facilitates improved flow recovery and reduced turbulence, leading to greater stability and lower acoustic power levels. The study underscores the importance of determining optimal vehicle positioning and longitudinal spacings to achieve aerodynamic and acoustic efficiency, establishing a foundation for sustainable transportation solutions.