Numerical solution for a two dimensional 3rd order nonlinear diff. eq.

In summary, there are multiple methods available for solving differential equations, including FDM, FEM, and numerical integration methods, each with its own advantages and limitations. The best method to use depends on the specific equation and boundary conditions being solved.
  • #1
Dor
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I'm a bit lost in all the numerous methods for solving differential equations and I would be very grateful if someone could point me to some direction.
I want to solve the following boundary conditioned differential equation:
$$a_1+a_2\nabla f(x,y)+a_3\nabla f(x,y)\cdot \nabla^2 f(x,y)+\left[a_4+a_5\nabla^2f(x,y)\right]^\frac{2}{3}\cdot\nabla^3 f(x,y)=0$$ ##a_i## - are constants

This equation is solved on a rectangular domain. let say for a start that the boundaries are:
##f(0,y)=0##
##f(x,0)=0##
##f(x,a)=C_1##
##\nabla f(b,y)=C_2##
##(a,b)## - Is the corner of the rectangle and ##C_1,C_2## are known constants.

  • ##f## - represents electric potential
  • ##\nabla f## - represents electric field
  • ##\nabla^2 f## - represents small excess charge density
  • To simplify the equation I can perform a first order expansion to ##\nabla^2f(x,y)## because it is very small. Than I can solve it rather easily using finite difference method, but I really prefer not to neglect this term ##\left[\nabla^2f(x,y)\right]##.
Thanks again
 
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  • #2
for your help!One of the most commonly used methods for solving differential equations is the Finite Difference Method (FDM). This method involves approximating the derivatives of the equation with finite differences, which are then used to solve the equation numerically. This method works well for equations with relatively simple boundary conditions and can also be used to solve systems of equations. Another widely used method is the Finite Element Method (FEM), which involves discretizing the domain into elements, and then constructing a solution from these elements. This method is often used for more complex boundary conditions and can also be used to solve systems of equations. Finally, there are numerical integration methods such as the Runge-Kutta method, which involve breaking up the domain into small intervals and then numerically integrating the equation over each interval. These methods are often used for equations with nonlinear terms or when the boundary conditions are too complex for the finite difference or finite element methods.
 

1. What is a numerical solution for a two-dimensional 3rd order nonlinear differential equation?

A numerical solution for a two-dimensional 3rd order nonlinear differential equation is a method of approximating the solution to the equation using a series of discrete points instead of an analytical solution. This is often necessary for complex equations that cannot be solved analytically.

2. How is a numerical solution different from an analytical solution?

An analytical solution is a closed-form expression that gives the exact solution to a differential equation. A numerical solution, on the other hand, uses numerical methods to approximate the solution at discrete points. While an analytical solution is often more accurate, it may not be possible to obtain for all equations, making numerical solutions more practical in some cases.

3. What are some common numerical methods used for solving two-dimensional 3rd order nonlinear differential equations?

Some common numerical methods for solving two-dimensional 3rd order nonlinear differential equations include the finite difference method, the finite element method, and the Runge-Kutta method. These methods involve breaking down the equation into smaller, solvable parts and using iterative processes to approximate the solution.

4. How do you choose the appropriate numerical method for a specific differential equation?

The choice of numerical method depends on various factors, including the type of differential equation, the boundary conditions, and the desired level of accuracy. It is important to carefully analyze these factors and choose a method that is most suitable for the specific equation at hand.

5. What are some applications of numerical solutions for two-dimensional 3rd order nonlinear differential equations?

Numerical solutions for two-dimensional 3rd order nonlinear differential equations have many real-world applications in fields such as physics, engineering, and economics. They are often used to model complex systems and predict their behavior, such as the motion of fluids, the growth of populations, and the spread of diseases.

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