Now trying to loop my code for lambda and calculate a CL for each lambda but my code runs only twice.

Question

Shawn Alcorn 2022-3-5

0
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https://ww2.mathworks.cn/matlabcentral/answers/1664164-now-trying-to-loop-my-code-for-lambda-and-calculate-a-cl-for-each-lambda-but-my-code-runs-only-twice

回答： Torsten 2022-3-5

My code for the for loop for lambda only runs once but I need it to run for each value of lambda and save the CL value for each one.

clc; clear all; close all
N=20;                                               
V_inf = 50;
for lambda = linspace(0,1,20)
    S = 39.2699;
    AR = 10.1859;
    AoA = 8; % Angle of Attack in degrees
    b = 20;
    alpha_0 = 0; % Zero lift angle of attack is 0 due to airfoil being symmetric
    cr = (2*b)/(AR*(lambda+1));
    ct = cr*lambda;
    i = 1;
    alpha   = AoA   * (pi/180);
    alpha_0 = alpha_0 * ones(N,1);
    Ntheta = N;                                        % Number of theta = 20
    theta = linspace(.01,pi-.01,Ntheta);                % Set the value of theta
    for k = 1:Ntheta                                    % Calculate each theta
        y = (b/2)*cos(theta(k));
        if theta(k) <= pi/2
            c = (2/b)*cr*(1-lambda)*y+cr;
        else
            c = -(2/b)*cr*(1-lambda)*abs(y)+cr;
        end
        if length(alpha) == 1
            alpha   = alpha * ones(N,1);
        end
        if length(c) == 1
            c       = c * ones(N,1);
        end
        C = zeros(Ntheta,N);                            
        B = zeros(Ntheta,1);                            
        for j = 1:Ntheta                                
            for n = 1:N
                   C(j,n) = 2*b/(pi*c(j)) * sin(n*theta(j)) + n * sin(n*theta(j))/sin(theta(j));
            end
                B(j,1) = alpha(j,1) - alpha_0(j,1);
        end
        A = inv(C)*B;
        Gamma   = zeros(Ntheta,1);                      
        alpha_i = zeros(Ntheta,1);                      
            for n = 1:N
                Gamma(j,1)   = Gamma(j,1) + 2*b*V_inf * A(n) * sin(n*theta(j));
                alpha_i(j,1) = alpha_i(j,1) +       n * A(n) * sin(n*theta(j))/sin(theta(j));
            end
    end
    A1(i) = A(1);
    CL(i) = AR*A1*pi;
    i = i +1;
end