How do I modify my code to get rid of this error: "Index exceeds the number of array elements. Index must not exceed 1. Error in AEM614HW2Q2 (line 35) "

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Shawn Alcorn
Shawn Alcorn 2022-3-5
回答： David Hill 2022-3-5
This is my error.
Index exceeds the number of array elements (1).
Error in HW2P2 (line 35)
C(j,n) = 2*b/(pi*c(j)) * sin(n*theta(j)) + n * sin(n*theta(j))/sin(theta(j));
clc; clear all; close all
N=500;
V_inf = 50;
i = 1;
lambda = .5; %linspace(0,1,N)
S = 39.2699;
AR = 10.1859;
alpha = 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;
for theta = linspace(.001,pi-.001,20);
y = (b/2)*cos(theta);
if theta <= pi/2
c = (2/b)*cr*(1-lambda)*y+cr;
else
c = -(2/b)*cr*(1-lambda)*abs(y)+cr;
end
alpha = alpha * pi/180;
alpha_0 = alpha_0 * pi/180;
if length(alpha) == 1
alpha = alpha * ones(N,1);
end
if length(alpha_0) == 1
alpha_0 = alpha_0 * ones(N,1);
end
if length(c) == 1
c = c * ones(N,1);
end
C = zeros(N,N);
B = zeros(N,1);
for j = 1:N
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 = C\B;
Gamma = zeros(N,1);
alpha_i = zeros(N,1);
for j = 1:N
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
end
A1(i) =A(1);
Cl(i) = AR*pi*A1;

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采纳的回答

David Hill
David Hill 2022-3-5
C(j,n) = 2*b/(pi*c(j)) * sin(n*theta) + n * sin(n*theta)/sin(theta);%get rid of theta(j) theta is scalar, cannot index >1 into it

更多回答（1 个）

Walter Roberson
Walter Roberson 2022-3-5
for theta = linspace(.001,pi-.001,20);
theta is a scalar
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
but there theta has to be a vector of length N

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