MATLAB Answers

Plot not generating graph

20 views (last 30 days)
I have the below two functions and script below. I am trying to plot (a,ratio), but my graph is coming up blank?
Could someone please take a look at what Im doing wrong?
function [CL,CD] = CL_and_CD(a)
%CL_and_CD accepts alpha input,returns two outputs CL/CD
% Calculates the lift and drag co-efficients "CL" & "CD"
CL = (4.47*(10^-5*(a.^3))+(1.15*(10^-3)*(a.^2))+(6.66*(10^-2).*a)+1.02*(10^-1));
CD = (5.75*(10^-6*(a.^3))+5.09*(10^-4*(a.^2))+1.81*(10^-4.*a)+1.25*(10^-2));
end
function [ratio] = L_to_D(CL,CD)
%L_to_D accepts two inputs and returns one output
%Accepts inputs for CL & CD, and produces the Lift to Drag ratio.
ratio= CL/CD;
end
%Input
a=(-2:0.1:22);
%Call to function CL_and_CD
[CL,CD]=CL_and_CD(a);
%Call to function Ratio
[ratio]= L_to_D(CL,CD);
%Plot
plot(a,ratio);
xlabel('Angle of attack (\alpha)');
ylabel('Lift to Drag Ratio');
title('Lift to Drag Ratio by Angle of attack (\alpha)');

Accepted Answer

Star Strider
Star Strider on 3 Mar 2021
Do element-wise division in ‘L_to_D’:
ratio= CL./CD;
Then it works and the plotted curve appears!
  2 Comments
Star Strider
Star Strider on 3 Mar 2021
As always, my pleasure!

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!