Resonance frequency in enclosures

Hi, I want to know how to make a code to know the resonance frecuency with different modes. The formula is the following but in nx, ny, nz I want to change the modes until (4,4,4), I tried to use a "for" and "break" but I failed completely.

I wanted the results to be shown in a table, where I only have to change the lenght of the enclosure (lx, ly, lz).

If someone could help me I would be completely grateful.

Answer 1

[Stephan]

Hi,

you can use this function:

function Frequencia_Table = Frequencia(v,lx,ly,lz)
% Building the array of values
nx = [zeros(5,1); repelem([1:4]',6,1)];
ny = [0; repmat(repelem([1 2 0]',2,1),4,1); 1; 1; 2; 2];
nz = [repmat([1;0],14,1); 1];
Freq = [nx, ny, nz, nan(size(nx,1),1)];

% Function handle
f = @(lx,ly,lz) v/2.*sqrt((nx./lx).^2 + (ny./ly).^2 + (nz./lz).^2);

% Calculate Frequencies (lx = 2, ly = 3, lz = 4) --> Enter the lengths here
Freq(:,4) = f(lx,ly,lz);

% Create a table of the results
Frequencia_Table = table(Freq(:,1),Freq(:,2),Freq(:,3),Freq(:,4),'VariableNames',{'Nx','Ny','Nz','Frequencia'});
end

Save it as Frequencia.m inside your Matlab project folder. Then call the function like this:

% Call the function with v=0.2, lx=2, ly=3, lz=4 and save the result in the variable res
res = Frequencia(0.2,2,3,4)

which gives the following result:

res =

  29×4 table

    Nx    Ny    Nz    Frequencia
    __    __    __    __________

    0     0     1         0.025 
    0     1     0      0.033333 
    0     1     1      0.041667 
    0     2     0      0.066667 
    0     2     1        0.0712 
    1     0     0          0.05 
    1     0     1      0.055902 
    1     1     0      0.060093 
    1     1     1      0.065085 
    1     2     0      0.083333 
    1     2     1      0.087003 
    2     0     0           0.1 
    2     0     1       0.10308 
    2     1     0       0.10541 
    2     1     1       0.10833 
    2     2     0       0.12019 
    2     2     1       0.12276 
    3     0     0          0.15 
    3     0     1       0.15207 
    3     1     0       0.15366 
    3     1     1       0.15568 
    3     2     0       0.16415 
    3     2     1       0.16604 
    4     0     0           0.2 
    4     0     1       0.20156 
    4     1     0       0.20276 
    4     1     1       0.20429 
    4     2     0       0.21082 
    4     2     1        0.2123

Best regards

Stephan

[Karla Stephany Rosas Galván]

Thank you so much Stephan, you're a master!