function [F12, A1, F21, A2] = orthoplate2plate(w, h, l) %[F12, A1, F21, A2] = orthoplate2plate(w, h, l) % % Description: % % View factor between two orthogonal rectangular surfaces. % % Inputs: % % w = width of base rectangle surface % h = height of orthoganal rectangular surface % l = depth of rectangle surfaces % % Outputs: % % F12 = view factor from lower rectangle to vertical rectangle % A1 = area of the lower rectangle % F21 = view factor from vertical rectangle to lower rectangle % A2 = area of the upper rectangle % % Reference: % % A Catalog of Radiation Heat Transfer Configuration Factors, % third edition, John R. Howell, The University of Texas at Austin % C-14: Two finite rectangles of same length, having one common edge, % and at an angle of 90o to each other. % http://www.thermalradiation.net/sectionc/C-14.html % %========================================================================== if l <= 0.0 error('FATAL ERROR in orthoplate2plate: depth of the plates, l = %d, must be greater than zero.',l) end A1 = w*l; % lower plate area A2 = h*l; % vertical plate area H = h/l; W = w/l; F12 = (1/(pi*W))*(W*atan(1/W) - sqrt(H^2 + W^2)*atan(sqrt(1/(H^2 + W^2))) ... + H*atan(1/H) + (1/4)*log((((1 + W^2)*(1 + H^2))/(1 + W^2 + H^2)) ... *((W^2*(1 + W^2 + H^2)/((1 + W^2)*(W^2 + H^2)))^(W^2)) ... *((H^2*(1 + W^2 + H^2)/((1 + H^2)*(W^2 + H^2)))^(H^2)))); F21 = F12*A1/A2; % F12*A1 = F21*A2