The effect of scattering on heat transfer in boundary-layer flows over a flat plate, over a 90-deg wedge, and in stagnation flow is investigated. To this end, a linear anisotropic scattering model is employed. The P-3 and P-l approximation methods are used to analyze the radiation part of the problem. The complete nonsimilar boundary-layer equations are solved by an implicit collocation procedure. Comparisons with the existing exact results for the case of isotropic scattering show that, overall, the P-3 approximation is more accurate than the P-\ approximation in predicting the total heat flux at the wall. Scattering generally leads to a reduction in the total heat flux. The degree of anisotropy can have a significant effect on the heat transfer in the boundary layer. The total heat flux for a forward-scattering fluid can be greater than that for a nonscattering fluid, depending on the value of the scattering albedo and the forward-backward scattering parameter.
Nomenclature= forward-backward scattering parameter = dimensionless blackbody emissive power, B 4 = blackbody emissive power, dT 4 = dimensionless stream function = intensity of radiation =kth moment of intensity given by Eq. a B e b f / i k j k k = thermal conductivity TV = conduction-radiation parameter, k ( K + a) /4aT 3 00 m = constant, a I (2ir + a ) Nu x = local Nusselt number p = phase function P n = Legendre polynomial of the first kind of degree n Pr = Prandtl number q r , Q r = radiative heat flux, Q r = q r /4dT 4 00 Q w > Gw = total heat flux at the wall, Q w = q w /4aT 4 00Re x = Reynolds number, £/« (x) xl v T = temperature T w = wall temperature r^ = external flow temperature t/oo (x) = external flow velocity, ~ x m x,y = physical coordinates along and normal to the wall a = wedge angle, rad j8 = polar angle f = nonsimilarity variable, (K + a)x/Re'£ i] = similarity variable, yRe'^/x 6 = dimensionless temperature, 77 T6 W = dimensional wall temperature, T W /T W K = absorption coefficient X = scattering albedo jit = direction cosine, cos/3 a = scattering coefficient a = Stefan-Boltzmann constant T = optical variable, ft = solid angle