Numerically solving coupled DEs?

  • Thread starter gyver
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Hi folks!

I'm trying to (numerically) find a steady-state solution for [tex]N_b[/tex] and [tex]N_w[/tex] in the following set of coupled DEs using the software package Matlab:

[tex]
\left{
\begin{array}{l}
\frac{\delta N_b}{\delta t} = P_b(N_b) - N_b \cdot \left( \frac{1}{\tau_b} - \frac{1}{\tau_c}D \right)\\
\frac{\delta N_w}{\delta t} = \frac{N_b}{\tau_c} - \frac{N_w}{\tau_w(N_w)} - P_w(N_w)
\end{array}
\right.
[/tex]

where [tex]\tau_b[/tex], [tex]\tau_c[/tex] and [tex]D[/tex] are constants. Which way would be the right one to go?
 
Last edited:
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Remove the dimensions and write a program to do RK4 unless this is just for a class in which case RK2 or Euler's with really small step is easier.
 

HallsofIvy

Science Advisor
Homework Helper
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I'm don't know MatLab but I'd run two Runge Kutta 4th order (RK4) algorithms simultaneously, using the current values for Nb and Nw in each formula.
 

J77

1,070
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What form do [tex]P_b[/tex] and [tex]\tau_w[/tex] take?
 

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