The results on an investigation of nonequilibrium uv radiation in the systems of molecular bands NO and (12) in a shock layer in air are presented. The studies included the experiments on a measurement + N 2 of the nonequilibrium radiation behind a strong shock wave in an electric arc-driven shock tube within the range of shock-wave velocity change V s = 5 to 10 km/s at the initial air pressure P 1 = 0.1 torr, and numerical simulation of radiation processes behind the shock wave and in a hypersonic viscous shock layer, where the ow was simulated on the basis of Navier -Stokes equations. A numerical model of the radiation behind the strong shock wave has been used to verify a kinetic scheme of radiation processes by comparison with experimental results. Examples of emission calculations in the NO and (12) sys-+ N 2 tems for the conditions of a ight test are presented. Nomenclature B = rotational constant c = speed of light, cm /s D = energy of dissociation, K e = electron H = ight altitude, km h = Planck's constant I = radiation intensity, W /cm 3 sr mm k = rate constant of reaction m = mass, g n = concentration, cm 2 3 P = pressure, torr R = radiance, W /cm 2 sr mm T = temperature, K t = time, s or ms U = rate of electron energy exchange V = ight or shock wave velocity, km /s v = vibrational number x = distance behind shock wave, cm y = stagnation line distance, cm b, g = parameters in vibration -dissociation model l = wavelength, nm or mm u = characteristic vibrational temperature, K n = collision frequency, s 2 1 s = cross section, cm 2 t = time, lifetime, s, ns, or ms v 0 , v 0 x 0 , v 0 y 0 , v 0 z 0 = vibrational constants ai = associative ionization e = electron, electronic el = elastic f = forward m = maximum R = rotational r = reverse s = shock-wave condition v = vibrational 1 = condition ahead of a shock wavè = freestream condition Superscripts 9 = upper excited state 0 = lower excited state

A new implicit monotonized scheme of second-order accuracy and Newton's method for solving the grid equations approximated the Navier-Stokes equations were developed to simulate the two-dimensional hypersonic viscous flow about a plate located in the wakes of a cylinder. The strong influence of the geometrical factor of interference between a plate and a cylinder (characterized by the normalized distance between the bodies) on skin friction and heat flux along the plane and cylinder surfaces have been found The changes of temperature, pressure and velocity fields in the wake behind the cylinder have been analyzed. Nomenclature C f = local skin friction coefficient c p = specific heat at constant pressure c v = specific heat at constant volume E = flux-vector in curvilinear coordinate system, Eqs.(l),(2) e = total energy per unit volume, pfcj'+tf + vO/2) G = flux-vector in curvilinear coordinate system, Eqs.(l),(2) H = total enthalpy per unit volume, c p T + (u 3 + v 7)/! h = node size J = Jacobian of the coordinates transformation

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The flow structure about a segmented projectile in hypersonic turbulent flow has been studied. The Reynoldsaveraged Navier-Stokes equations were solved numerically by application of the implicit monotonized scheme of second-order accuracy, the modified Newton's method, and the Christoffel-Schwarz grid-transformation technique. A strong interference effect has been found. The effect can be characterized by non-monotonous distributions of skin friction, heat flux and pressure along the second segment of the projectile. Nomenclature C f = local skin friction coefficient C p = pressure coefficient c p , c = specific heats at constant pressure and volume D = diameter of the projectile E, G = flux-vectors in curvilinear coordinate system, Eqs.(l),(2) e = total energy per unit volume, p(c^T+(u~ ~ v~)/2) H = total enthalpy per unit volume, c p T + (if-f v~)/2 /? = node size J = Jacobian of the coordinates transformation