Difference between revisions of "NumMethodsPDEs"

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<math> Au_{xx} + Bu_{xy} + Cu_{yy} + Du_x + Eu_y + Fu = G </math>
 
<math> Au_{xx} + Bu_{xy} + Cu_{yy} + Du_x + Eu_y + Fu = G </math>
  
* '''Parabolic'''
+
* '''Parabolic''':  <math>B^2 - 4AC = 0</math>.  This family of equations describe heat flow and diffusion processes.
* '''Hyperbolic'''
+
* '''Hyperbolic''':  <math>B^2 - 4AC > 0</math>.  Describe vibrating systems and wave motion.
* '''Elliptic'''
+
* '''Elliptic''':  <math>B^2 - 4AC < 0</math>.  Steady-state phenomena.
 
 
  
  
 +
Taylor Series:
  
 
<math> f(x + h) = f(x) + \frac{f'(x)}{1!}h + \frac{f^{(2)}(x)}{2!}h^2 + \cdots + \frac{f^{(n)}(x)}{n!}h^n + R_n(x)</math>
 
<math> f(x + h) = f(x) + \frac{f'(x)}{1!}h + \frac{f^{(2)}(x)}{2!}h^2 + \cdots + \frac{f^{(n)}(x)}{n!}h^n + R_n(x)</math>

Revision as of 17:25, 17 January 2011

Numerical Methods for PDEs: Solving PDEs on a computer

Introduction

Looking at Nature

A second-order linear equation in two variables:

[math]\displaystyle{ Au_{xx} + Bu_{xy} + Cu_{yy} + Du_x + Eu_y + Fu = G }[/math]

  • Parabolic: [math]\displaystyle{ B^2 - 4AC = 0 }[/math]. This family of equations describe heat flow and diffusion processes.
  • Hyperbolic: [math]\displaystyle{ B^2 - 4AC \gt 0 }[/math]. Describe vibrating systems and wave motion.
  • Elliptic: [math]\displaystyle{ B^2 - 4AC \lt 0 }[/math]. Steady-state phenomena.


Taylor Series:

[math]\displaystyle{ f(x + h) = f(x) + \frac{f'(x)}{1!}h + \frac{f^{(2)}(x)}{2!}h^2 + \cdots + \frac{f^{(n)}(x)}{n!}h^n + R_n(x) }[/math]