Extensive efforts have been directed toward the development of the means by which the ow separation asymmetry occurring on an axisymmetric slender forebody at very high angles of attack could be controlled in order to improve the agility of advanced aircraft and missiles. To control the asymmetric ow separation represents a great challenge, and only a few of the investigated ow-control concepts have led to viable solutions. The uid-mechanical processes associated with steady and alternating-pulsed blowing applications are analyzed in an effort to de ne ow mechanisms that can cause the observed anomalous control characteristics. Nomenclatureb ¤ = wing span or maximumm body diameter C P m = dimensionless mass ow rate of jet blowing C ¹ = dimensionless ow-momentum-rate of jet blowing D = maximum body diameter L = microrod extension (Fig. 4) l = body length = x location for L D 0 (Fig. 4) M = Mach number N = normal force, coef cient C N D N =.½ 1 U 2 1 /S ¤ ; c n D @C N =@ » n = yawing moment, coef cient C n D n=.½ 1 U 2 1 =2/S ¤ b ¤ Re = Reynolds number based on D and U 1 r = local body radius r B = base radius r N = nose radius S ¤ = reference area, projected wing area or ¼D 2 =4 T = period of alternating blowing cycle t = time t c = convection time, D l=U 1 t ¤ = dimensionless time, t ¤ D x tan ®=r (Fig. 17) U 1 = freestream velocity x = axial body-xed distance from the nose tip Y = side force, coef cient C Y D Y=.½ 1 U 2 1 /S ¤ ; c y D @C Y =@» ® = angle of attack 1 = increment µ A = apex half angle of slender forebody » = dimensionless x coordinate, D x=D ½ 1 = freestream uid density ¿ = time duration that the valve is open during the blowing cycle Á = azimuth of blowing ori ce, Á > 0 on the startboard side

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A critical examination of recent dynamic test results obtained at high angles of attack reveals that various kinds of ground facility interference effects can distort the measurements. Particular problems are posed by both asymmetric and symmetric support structures. It is also found that the fuselage-like structures commonly used to attach a sting or strut to the model can cause unacceptable distortion of the high-alpha steady and unsteady aerodynamic characteristics. Nomenclatureyawing moment coefficient, C n = (p 00 U 2^/ 2)Sb p = static pressure coefficient, C P = (P ~ p~)/(p~Ul/2) S = reference area, projected wing area s = local half-span t = time U = horizontal velocity w = width of test section x = axial body-fixed coordinate y = spanwise body-fixed coordinate a = angle of attack /3 = angle of sideslip A = increment or amplitude 77 = dimensionless y coordinate, A = leading-edge sweep angle f = dimensionless x coordinate, p = air density = roll angle $ = coning angle (1 =' dimensionless coning rate, ij/b/2U x ; if/l/2U x for body alone a) = angular frequency, 2irf a) = reduced frequency, Subscripts A = apex B = vortex breakdown V = vortex 3° = freestream conditions Differential Symbols .yls , x/c Presented as Paper 95-0795 at the AIAA 33rd Aerospace Sciences