Mach Number Area Relation Several Inputs

Question

Steven Castrillon 2019-9-30

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/482921-mach-number-area-relation-several-inputs

评论： Jim Riggs 2019-10-1

在 MATLAB Online 中打开

The following code inputs a single input (ARatio) and outputs two terms (Msub) & (Msup)

I want to be able to input several ARatio values, more specifically an array from 0.1 to 10 with an increment of 0.1

and have Msub & Msup for each of these ARatio stored in an array in order to plot ARatio and Mach number.

clear;
clc;
%% INPUTS
% Define some paramters
g   = 1.4;
gm1 = g-1;
gp1 = g+1;
% Define anonymous function with two inputs (M and ARatio)
% - Will be used in the methods below
% - Pass M and ARatio as arguments to AM_EQN to get function value
% -     funVal = AM_EQN(M,ARatio)
AM_EQN = @(M,ARatio) sqrt((1/M^2)*(((2+gm1*M^2)/gp1)^...
                            (gp1/gm1)))-ARatio;
% Solve for Msub and Msup using this area ratio (A/A*)
ARatio = 1.5;
% Error tolerance
errTol = 1e-4;
% Flags for printing iterations to screen
verboseBisection   = 0;
verboseIncremental = 0;
%% MATLAB SOLVER
% Set up the solver
problem.objective = @(M) (1/M^2)*(((2+gm1*M^2)/gp1)^(gp1/gm1))-ARatio^2;    % Objective function
problem.solver    = 'fzero';                                                % Find the zero
problem.options   = optimset(@fzero);                                       % Default options
% Solve subsonic root
problem.x0 = [1e-6 1];                                                      % Subsonic solver bounds
Msub       = fzero(problem);                                                % Solve for subsonic M
problem.x0 = [1+1e-6 50];                                                   % Supersonic solver bounds
Msup       = fzero(problem);                                                % Solve for supersonic M
% Print solutions to command window
fprintf('==== MATLAB SOLVER ====\n');
fprintf('Msub: %3.4f\n',Msub);
fprintf('Msup: %3.4f\n',Msup);
fprintf('=======================\n\n');

4 个评论
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Star Strider 2019-9-30

Related: Area Mach Number Relation

Jim Riggs 2019-10-1

Thank you. It works.

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Answer 1

David Hill 2019-10-1

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/482921-mach-number-area-relation-several-inputs#answer_394220

在 MATLAB Online 中打开

function [Msub,Msup] = sub_super(ARatio)%ARatio needs to be >1
g   = 1.4;
gm1 = g-1;
gp1 = g+1;
Msub=zeros(size(ARatio));
Msup=zeros(size(ARatio));
for i=1:length(ARatio)
    problem.objective = @(M) (1/M^2)*(((2+gm1*M^2)/gp1)^(gp1/gm1))-ARatio(i)^2;    
    problem.solver    = 'fzero';                                              
    problem.options   = optimset(@fzero);                                      
    problem.x0 = [1e-6 1];                                                     
    Msub(i)       = fzero(problem);                                               
    problem.x0 = [1+1e-6 50];                                                   
    Msup(i)       = fzero(problem);  
end
plot(ARatio,Msub);
hold on
plot(ARatio,Msup);
end