NUMERICAL INTEGRATION OF THE 1-D WAVE EQUATION AS AN EXAMPLE OF A HYPERBOLIC PDE USING MATHEMATICA
Skender AVDIJI, Musa AJETI
Abstract
Hyperbolic partial differential equations (PDEs) are a distinct class of equations that manifest wave-like behaviors, characterized by solutions that propagate along defined characteristics. These equations are pivotal in the exploration of dynamic phenomena across various fields such as physics and engineering, particularly in the analysis of waves and vibrations.
General form of second-order linear PDEs in two variables with constant coefficients:
a (∂^2 u)/(∂x^2 )+b (∂^2 u)/∂x∂y+c (∂^2 u)/(∂y^2 )+d ∂u/∂x+e ∂u/∂x+f u=g (1)
Here u=u(x,y), and a,b,c,d,e,f and g are functionsof x and y only- they do not depend on u. If g=0, the equation is said to be homogeneous.
b^2-4ac is called the discriminant.
If b^2-4ac>0 then the equation (1) is called hyperbolic.
Among the hyperbolic PDEs, the wave equation is renowned for describing the propagation characteristics of various types of waves, such as sound and electromagnetic waves. The one-dimensional wave equation is expressed as:
(∂^2 u)/(∂t^2 )-c^2 (∂^2 u)/(∂t^2 )=0 (2)
Here, c signifies the speed of wave propagation.
The numerical solution of the wave equation, being a central hyperbolic PDE, is typically approached via finite difference methods. This technique discretizes the continuous domain into a computational grid and employs finite difference approximations for the derivatives. Utilizing Mathematica, one can leverage its robust built-in functions, such as NDSolve, to tackle initial-boundary value problems for PDEs effectively. Alternatively, for those preferring a more hands-on approach, implementing a finite difference method directly within Mathematica offers a comprehensive understanding and customization of the numerical solution process.
Pages: 434 - 444