3D transonic flow over swept and unswept wings with an J-78 airfoil at spanwise sections is studied numerically at negative and\nvanishing angles of attack. Solutions of the unsteady Reynolds-averaged Navier-Stokes equations are obtained with a finite-volume\nsolver on unstructured meshes. The numerical simulation shows that adverse Mach numbers, at which the lift coefficient is highly\nsensitive to small perturbations, are larger than those obtained earlier for 2D flow. Due to the larger Mach numbers, there is an\nonset of self-exciting oscillations of shock waves on the wings. The swept wing exhibits a higher sensitivity to variations of the\nMach number than the unswept one
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