ABSTRACT
In order to optimize the geometry of the body’s cross-section for transportation purposes and also to obtain higher aerodynamic efficiencies, non-circular bodies have gained substantial attention by many researchers. In this work, the aerodynamic characteristics of two bodies having the same cross-sectional areas, but different shapes (one circular and one square with round comers) have been compared. In order to differentiate the non-circularity and the fin effects, the bodies with no fins have been considered. A three-dimensional, compressible, stationary, viscous, turbulent flow has been simulated using the FLUENT CFD code with the standard k-ε model and adaptive grids. The free stream Mach number is 0.83. The results have been compared with the experimental data and the data obtained from two semi-empirical codes, Digital DatCom and Missile DatCom. The results indicate that, although the semi-empirical codes were developed to calculate the aerodynamic parameters of bodies, the accuracy of CFD results is better and more reliable than that of semi-empirical codes. In addition, changing the cross section from circular to square increase the lift coefficient and aerodynamic performance, especially at low angles of attack. By changing the cross section from circular to square, the drag coefficients remain constant at low angles of attack but at higher angles, drag coefficient somehow increase.
