Keep getting the "Array indices must be positive integers or logical values." error
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Tom Oud
el 12 de Dic. de 2018
Comentada: Tom Oud
el 13 de Dic. de 2018
Trying to simulate a water rocket using matlab, however I can't get my for loop to work properly.
This is what I have so far:
close all
clear all
P0 = 6e5; %Pa
Pout = 1e5; %Pa
V0 = 2; %l
V = 1.5; %l
gamma = 1.4;
rho_w = 998; %kg/m^3
%Pin = P0*(V/V0).^-gamma;
dt = 0.01;
t = 1:dt:100;
Ve(1) = 0; %m/s
Pin(1) = 6e5; %Pa
v0 = 0; %m/s
v = 0; %m/s
M0 = 0.1; %kg
M = M0 + (V0-V)*rho_w;
for i = 1:100
Pin(i+1) = Pin(i) - P0(V/V0).^-gamma;
Ve(i+1) = sqrt(2*(Pin(i) - P0)/rho_w);
%v = Ve*log(M0/M) + v0;
end
Really hoping one of you can enlighten me, because I'm completely lost here.
3 comentarios
Image Analyst
el 12 de Dic. de 2018
V/V0 = 1.5/2, not 0/0
madhan's Answer below lets the code run without error. No guarantee about the equations correctness though - I didn't try to verify them.
Guillaume
el 12 de Dic. de 2018
Oh! I didn't see that there were both V and V0 variables (uppercase) as well as v and v0 (lowercase).
That's really begging for trouble! You can be sure at some point the wrong case will be used. Never distinguish variable names just by casing.
Respuesta aceptada
madhan ravi
el 12 de Dic. de 2018
Pin(i+1) = Pin(i) - P0*(V/V0).^-gamma;
^----missed it
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