Simulation Of Flow Around A Bullet-Shaped Object

Abstract

The aerodynamic performance of external flow around streamlined bodies is an important aspect in many engineering applications, including aerospace, automotive, and projectile systems. The interaction between airflow and body geometry influences pressure distribution, velocity variation, wake formation, and aerodynamic drag. Although streamlined bodies are designed to minimise aerodynamic resistance, flow separation and wake development may still occur, especially at higher flow velocities. These phenomena can significantly affect aerodynamic performance and energy efficiency. Therefore, an investigation is required to evaluate the influence of inlet velocity on the flow behaviour around a bullet-shaped object. The aim of this study is to investigate the aerodynamic characteristics of a bullet-shaped object subjected to different inlet velocities. A numerical approach was employed to analyse pressure distribution, velocity distribution, streamline behaviour, and drag coefficient around the geometry. Three inlet velocities, namely 10 m/s, 20 m/s, and 30 m/s, were considered. The results showed that the highest pressure occurred at the nose region of the bullet-shaped object due to flow stagnation, while a low-pressure wake region developed behind the rear section. Velocity contours revealed flow acceleration around the curved surface of the body followed by flow separation downstream. Streamline analysis indicated the formation of recirculation zones and vortex structures behind the object. The drag coefficient increased from 2.6717 at 10 m/s to 8.4498 at 20 m/s and 16.8668 at 30 m/s. Furthermore, the grid independence test demonstrated that the difference between the two finest meshes was only 2.82%, indicating that the numerical solution had approached mesh-independent behaviour. In conclusion, inlet velocity significantly influenced the aerodynamic characteristics of the bullet-shaped object. Higher velocities generated larger wake regions, stronger recirculation zones, and greater drag coefficients. The study successfully demonstrated the relationship between velocity variation and aerodynamic performance of a bullet-shaped geometry.