Bullets and projectiles are relatively simple geometries, however, the physics of air around them is rather complex. While the most important parameter is accuracy, this depends on several things, such as the aerodynamics of the flying bullet. Drag, stability, moment, center of pressure are some of the most important quantities that can be determined by a CFD (Computational Fluid Dynamics) Simulation and what’s more, for several scenarios. Therefore, an airflow simulation in order to investigate the bullet aerodynamics is one of the services CFD Freelancing offers.
Subsonic bullet aerodynamics
Projectiles, such as air pellets, airsoft ammunition and paintball bullets are flying in the subsonic speed regime, that is, below the speed of sound. This means that the airflow around the bullet is fundamentally different as in case of a supersonic projectile. One example is the absence of shockwave. Bullet CFD analysis requires therefore additional attention when setting up the simulation environment.
Supersonic bullet aerodynamics simulation
Most of the bullets are fired above the sound speed and fly further in this speed regime until they hit the target. In front of the bullet a shockwave is clearly visible, also known as the bullet bow shockwave that is, a sudden jump in density. Riffles, guns and pistols ammunition belong to this speed regime.
What are the outcomes of a bullet CFD simulation?
The primary factors affecting the aerodynamics of a bullet in flight are the bullet’s shape and the rotation imparted by the rifling of the gun barrel. Rotational forces stabilize the bullet gyroscopically as well as aerodynamically, which can be of course simulated by CFD.
Effect of side wind on the bullet aerodynamics
Side wind has a great effect on bullet aerodynamics. This is something that a designer can not be hand-calculate, and very difficult to measure. CFD simulation is the best tool to analyse the aerodynamics, asymmetric forces and torque. The so-called Magnus effect can be investigated too. Forces acting sidewards can be calculated and analyzed for different wind scenarios. By adding turbulence analysis, we get a full picture about how the bullet performs in overall.
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