Tragopogon pratensis is a small herbaceous plant that uses wind as the dispersal vector for its seeds. The seeds are attached to parachutes that increase the aerodynamic drag force and increase the total distance travelled. Our hypothesis is that evolution has carefully tuned the air permeability of the seeds to operate in the most convenient fluid dynamic regime. To achieve final permeability,...

Abstract The NACA4415 airfoil was numerically simulated with the help of Fluent software to analyze its aerodynamic characteristics. Results are acquired as follows: calculation accuracy is much higher than that XFOIL software; result SST k - ω (sstkw) turbulence model closest experimental value; within a certain range, larger Reynolds number is, lift coefficient and lift-to-drag ratio will be,...

Aerodynamic parameters play a decisive role in the ballistic characteristics of projectile. How to accurately obtain aerodynamic projectile is an important task development process In order further improve identification accuracy drag coefficient, this paper generates huge data through numerical simulation and uses extreme learning method identify coefficient under three kinds noise conditions....