MATLAB: Plot earth atmospheric model

atmosphereelseififmodelmultipleplot

Hello! Relatively new user here, im trying to plot the model of the atmosphere (density,temperature,speed of sound, vs altitude) as found here:
https://www.grc.nasa.gov/WWW/K-12/airplane/atmosmet.html
and here:
https://www.grc.nasa.gov/WWW/K-12/airplane/sound.html
but im having trouble with the code, I dont really know what to do, that's why I am asking for a little help.The script runs but its not correct. I guess it is some kind of wrong usage of the if ifelse statements or even the way I created the height vector.
Any help would be appreciated. Thank you.

Best Answer

Hi,
Note how to use conditional operators [if... elseif.. else..end] within [for ... end] loop. The equations you have taken are corrected w.r.t nasa.gov info. T used in formulation of the speed of sound has to be absolute tempreature and thus: T = temp + 273.1
Here is the complete answer code:
h=linspace(0,100000);
temp=zeros(size(h));     % Memory allocation

pressure=zeros(size(h)); % Memory allocation
for ii = 1:numel(h)
    if h(ii)<11000
        temp(ii)=15.04-0.00649*h(ii);
        pressure(ii)=101.29*((temp(ii)+273.1)/288.08)^5.256;
    elseif  h(ii)>11000 && h(ii)<25000
        temp(ii)=-56.46;
        pressure(ii)=22.65.*exp(1.73-0.000157*h(ii));
    else                 
        temp(ii)=-131.21+0.00299*h(ii);
        pressure(ii)=2.488*((temp(ii)+273.1)/216.6)^(-11.388);
    end
end
  dens=pressure./(0.2869*(temp+273.1));  
  T = temp+273.1;
  speedofsound = sqrt(1.4*286*T);
  
  figure(1);plot(h,temp, 'r-*'); grid on, title('temp')
  figure(2);plot(h,dens, 'b-o'); grid on, title('dens')
  figure(3);plot(h, speedofsound, 'g-.x'); grid on, title('speed of sound')
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