a.b rahimi - Professor, Faculty of Engineering, Ferdowsi University of Mashhad, P. O. Box No. ۹۱۷۷۵-۱۱۱۱, Mashhad, Iran

Numerical methods are not always convergent especially in higher velocities when shock waves are involved. A comparison analysis is performed to study the supersonic flow over conical bodies of threedifferent cross sections circular, elliptic and squircle (square with rounded corners) shaped usingPerturbation techniques to find flow variables analytically. In order to find lift and drag forces the pressure force on the body is found, the component along x is drag and the component along z is lift.Three equations are obtained for lift to drag ratio of each cross section. The graphs for L/D show thatfor a particular cross section an increase in angle of attack, increases L/D. Comparing L/D in the three mentioned cross sections depicted that L/D is the greatest in squircle then in ellipse and the least in circle. The results are efficient in design of flying objects.

Supersonic Flow,Conical Bodies,Lift to Drag Ratio,Squircle Cross-section,Euler Equations,Perturbation Techniques