Study of supersonic intersection flowfield at modified wing-body junctions

Abstract

The problem of supersonic flow control using fillets and sweep for a wing-body junction has been investigated numerically using a three-dimensional Navier-Stokes code, which employs the MacCormack's time-split finite volume technique. An elliptic grid generation technique with direct control over spacing has been developed for constructing the grid at a filleted wing-body junction. The computed results for pressure distribution, particle paths, and limiting streamlines on the flat plate and fin surface for a swept fin show a decrease in the peak pressure on the fin leading edge and in the extent of the separated flow region. Moreover, the results for filleted juncture clearly show that the flow streamline patterns lose much of their vortical character with proper filleting. It has been demonstrated that fillets with a radius of three-and-one-half times the fin leading-edge diameter are required to weaken the vorticity in the horseshoe vortex by a factor of three for the Mach number and Reynolds number considered in the present study. Nomenclature a -speed of sound CFL = Courant-Friedrichs-Lewy number Cf = skin friction coefficient D = diameter of the fin E = total energy per unit mass £/ = specific internal energy, T/y(y -1) H = height of the fin / = index in % direction j = index in 17 direction k -index in f direction L£, L^ L{ = finite difference operators in £, 17, and f directions M = Mach number Pri -laminar Prandtl number Pr t -turbulent Prandtl number p = static pressure R = radius of the fillet at the juncture T = static temperature t = time q = vector of conserved variables u -velocity component in x direction v = velocity component in y direction w = velocity component in z direction x, y, z = global coordinates X Q = distance from the flat plate leading edge to fin leading edge y = ratio of specific heats, c p /c v At = time step used in the split operators d = boundary-layer thickness A = fin sweep angle X = second coefficient of viscosity, -%/* jLt = dynamic molecular viscosity £, y, f = body oriented coordinates p = density a = safety factor in the stability criteria equation w = vorticity magnitude Subscripts t2

Numerical prediction of the interference drag of a streamlined strut intersecting a surface in transonic flow

“…The Reynolds-averaged Navier-Stokes solutions obtained by Chen and Hung [19] on a cylinder perpendicular to a flat plate revealed that the main effect of increasing the Mach number is to produce a larger vortex structure because of the shock-wave/boundary-layer interaction. The Navier-Stokes solutions of Lakshmanan and Tiwari [85] showed that, by properly filleting the junction between a swept fin and a flat One application of the study of the flow around a fin perpendicular to a flat wall is the design of wing-fuselage junctions. Favorable aerodynamic interference was achieved between the wing and the fuselage by Pritulo et al [89].…”

“…Buning [82], McMaster and Shang [87], Knight et al [83], Chen and Hung [19], Lakshmanan and Tiwari [85,86], and Zemsch and Degrez [94]. Hung and Buning [82] performed an experiment to assess the influence of the thickness of the incoming boundary layer on the hoseshoe vortex forming at the junction.…”