抄録
This paper describes the theoretical consideration of wind penetration and heat transmission through the fabric layer fitting closely to the heated cylinder which is the simple model of clothing system. The wind penetration was assumed to follow Darcy's law and the streamlines of penetration flow in the fabrics near the stagnation point on the cylinder were found to be given by the hyperbolae including the unknown parameter ΔP* in relation to the differential pressure across the fabric layer. Under the existance of penetration flow, the heat transfer equation has the solution of temperature distribution approximated with the form of error function. This temperature distribution makes clear the resistance of fabric layer IF as the function of, ΔP* and where U: wind velocity, ρ: air density, Cp. air heat capacity, μ: air viscosity, ky: permeability of fabrics, λmy: thermal conductivity of fabrics, δ: thickness of fabrics.
Over-all resistance I at stagnation point of cylinder is the sum of IF and the resistance of external air film IA weighted by the conductive flux ratio, where IA is estimated by the heat transfer process of normal cylinder (without fabrics). Theoretically calculated results of I are most fitting the data in the case of the range of ΔP* from 0.2 to 0.5, in other words the value of differential pressure acting across the fabric layer on the stagnation should be about a half or a quarter of the dynamic pressure of wind. Then the magnitude of ΔP* seems to be reasonable and we conclude that Darcy's law and heat transfer equation are effective on the study of wind penetration and so the fabric layer is formulated by the three values of layer; Darcy's permeability ky thermal conductivity λmy and thickness δ.
