Create a matlab code with given chart

4 TYPES OF L/D VALUE İS GİVEN ON THE CHART AS İT SEEN. BUT WHEN WE WRİTE SOME L/D RATİOS WHICH IS NOT GIVEN IN THE CHART WE USE INTERPOLATION TO FOUND IT. FOR EXAMPLE İF I WANT TO FIND FOR L/D=0.60 HOW CAN I WRITE ITS MATLAB CODE AND CALCULATE IT?

Firstly, welcome to the forums.

While we are primarily here to help people with their Free Code Camp progress, we are open to people on other paths, too. Some of what you are asking is pretty trivial in the Free Code Camp context, so you might find that if you’re not getting the instruction and material you need in your current studies, the FCC curriculum will really help you get started. At a modest guess I’d say investing a 4-5 hours working through the curriculum here will really pay off. You can find the curriculum at https://www.freecodecamp.org/learn.

With your current questions, we don’t have enough context to know what you already know or don’t know, so it is impossible to guide you without just telling you the answer (which we won’t do).

It is pretty typical on here for people to share a codepen / repl.it / jsfiddle example of what they have tried so that anyone helping has more of an idea of what help is actually helpful.

Please provide some example of what you’ve tried and I’m sure you’ll get more help.

Happy coding :slight_smile:

d=input('enter a diameter value:'); %journal diameter (m)
l=input('enter a length value:');   %bearing length (m)
r=d/2;                              %radius (m)
c=input('enter a radial clearance:'); % radial clearance (m)
T1=input('assign an inlet temperature:'); %inlet temperature (celcius)
delta_T=input('enter temperature rise value:'); %assumed temperature rise (celcius)
W=input('enter a radial load on journal:');     %radial load on journal (N)
n_s=input('enter journal speed value of shaft:');       %journal speed (rev/sec)
P=W/(l*d);                                        %bearing pressure (N/m^2)
Tavg_vector=[10:10:140];                        %average temperature vector 
abs_vis_vector=[500 190 90 45 28 18 12 9 6.5 5.2 4.2 3.2 2.8 2.6]; % absolute viscosity vector
Tavg=T1+(delta_T/2);                            %average temperature (celcius)
fabs_vis_vector=csapi(Tavg_vector,abs_vis_vector); %cubic spline interpolation 
absolute_viscosity_value=fnval(fabs_vis_vector,Tavg); %absolute viscosity value mPa.s
absolute_viscosity_value=absolute_viscosity_value*10^-3; %absolute viscosity value Pa.s
Sc=((absolute_viscosity_value*n_s)/P)*(r/c)^2;           %sommerfeld number
%performance parameters for corresponding l/d ratio
if l/d==1
    % for l/d=1 performance parameters
    S_1=[0.0188 0.0446 0.121 0.264 0.631 1.33 ];
    % the corresponding vector for the minimum film thickness variable,h0/c
    hoc_1=[0.1 0.2 0.4 0.6 0.8 0.9 ];
    % the corresponding vector for the coefficient of friction variable, Rf /c
    Rfc_1=[1.05 1.70 3.2 5.79 12.8 26.4];
    % the corresponding vector for the volumetric oil-flow rate, Q/ (RcnL)
    Qc_1=[4.74 4.62 4.33 3.99 3.59 3.37];
    % the corresponding vector for side leakage flow/total flow, Qs/Q
    Qsc_1=[0.919 0.842 0.680 0.497 0.280 0.150]; 
elseif l/d==0.5
    % for l/d=0.5 performance parameters
    S_2=[0.0313 0.0923 0.319 0.779 2.03 4.31];
    % the corresponding vector for the minimum film thickness variable,h0/c
    hoc_2=[0.1 0.2 0.4 0.6 0.8 0.9];
     % the corresponding vector for the coefficient of friction variable, Rf /c
    Rfc_2=[1.60 3.26 8.10 17.0 40.9 85.6];
    % the corresponding vector for the volumetric oil-flow rate, Q/ (RcnL)
    Qc_2=[5.69 5.41 4.85 4.29 3.72 3.43];
    % the corresponding vector for side leakage flow/total flow, Qs/Q
    Qsc_2=[0.939 0.874 0.730 0.552 0.318 0.173];
elseif l/d==0.25
    % for l/d=0.25 performance parameters
    S_3=[0.0736 0.261 1.07 2.83 7.57 16.2];
    % the corresponding vector for the minimum film thickness variable,h0/c
    hoc_3=[0.1 0.2 0.4 0.6 0.8 0.9];
    % the corresponding vector for the coefficient of friction variable, Rf /c
    Rfc_3=[ 3.50 8.8 26.7 61.1 153.0 322.0];
    % the corresponding vector for the volumetric oil-flow rate, Q/ (RcnL)
    Qc_3=[5.91 5.60 4.99 4.37 3.76 3.45 ];
    % the corresponding vector for side leakage flow/total flow, Qs/Q
    Qsc_3=[0.945 0.884 0.746 0.567 0.330 0.180 ];
elseif l/d==inf 
    % for l/d=inf performance parameters
    S_4=[0.0115 0.021 0.0389 0.0626 0.123 0.240];
    % the corresponding vector for the minimum film thickness variable,h0/c
    hoc_4=[0.1 0.2 0.4 0.6 0.8 0.9];
    % the corresponding vector for the coefficient of friction variable, Rf /c
    Rfc_4=[0.961 1.20 1.52 2.57 4.80];
    % the corresponding vector for the volumetric oil-flow rate, Q/ (RcnL)
    Qc_4=[0.760 1.56 2.26 2.83 3.03];
    % the corresponding vector for side leakage flow/total flow, Qs/Q
    Qsc_4=[0 0 0 0 0 0 0 0 0];
end
if l/d==1
% To interpolate the data, the MATLAB function csapi(X,Y) is used:
fhoc_1 = csapi( S_1, hoc_1 );
ffc_1 = csapi( S_1, Rfc_1);
fQR_1 = csapi( S_1, Qc_1);
fQs_1 = csapi( S_1, Qsc_1);
% The values of the interpolated data functions at Sc are calculated with:
hc = fnval(fhoc_1, Sc); % ho/c 
fc = fnval(ffc_1, Sc);  %(r/c)f
Qc = fnval(fQR_1, Sc);  % Q/(r c n L)
Qsc= fnval(fQs_1, Sc);  % Qs/Q 
elseif l/d==0.5
% To interpolate the data, the MATLAB function csapi(X,Y) is used:
fhoc_2 = csapi( S_2, hoc_2);
ffc_2 = csapi( S_2, Rfc_2);
fQR_2 = csapi( S_2, Qc_2);
fQs_2 = csapi( S_2, Qsc_2);
% The values of the interpolated data functions at Sc are calculated with:
hc = fnval(fhoc_2, Sc); % ho/c
fc = fnval(ffc_2, Sc);  %(r/c)f
Qc = fnval(fQR_2, Sc);  % Q/(r c n L)
Qsc= fnval(fQs_2, Sc);  % Qs/Q
elseif l/d==0.25
% To interpolate the data, the MATLAB function csapi(X,Y) is used:
fhoc_3= csapi( S_3, hoc_3 ); 
ffc_3= csapi( S_3, Rfc_3 );  
fQR_3= csapi( S_3, Qc_3 );   
fQs_3= csapi( S_3, Qsc_3 );  
% The values of the interpolated data functions at Sc are calculated with:
hc = fnval(fhoc_3, Sc);  % ho/c
fc = fnval(ffc_3, Sc);   %(r/c)f
Qc = fnval(fQR_3, Sc);   % Q/(r c n L)
Qsc= fnval(fQs_3, Sc);   % Qs/Q
else l/d==inf
% To interpolate the data, the MATLAB function csapi(X,Y) is used:
fhoc_4 = csapi( S_4, hoc_4 );
ffc_4 = csapi( S_4, Rfc_4 );
fQR_4 = csapi( S_4, Qc_4 );
fQs_4= csapi( S_4, Qsc_4 );
% The values of the interpolated data functions at Sc are calculated with:
hc = fnval(fhoc_4, Sc);  % ho/c
fc = fnval(ffc_4, Sc);   %(r/c)f
Qc = fnval(fQR_4, Sc);   % Q/(r c n L)
Qsc= fnval(fQs_4, Sc);   % Qs/Q
end

4 types of l/d ratio is given on the chart as it seen. but when we write a l/d ratio which is not given on the chart we use interpolation to found it. for example if ı want to find l/d=0.60 how can ı write ıts matlab code and calculate it?

I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).