Boundary Conditions Laplace

In summary, the speaker is discussing using Finite Difference Method and the stream function to solve a simplified version of the Laplace equation in a code made in C. They are able to simulate the current pattern using boundary conditions shown in a sketch, but they are wondering how to introduce the effect of the magnetic field. The suggested solution is to introduce Neumann conditions in certain points to simulate the force of the magnetic field. Alternatively, the magnetic field can be more accurately modeled by adding additional terms to the finite difference equation.
  • #1
Tempa
7
0
Hi there, I am solving laplace equation in a code i made in C. I am using Finite Difference Method in order to simulate the current pattern. I used the stream function to do that.


       Electrode
0.--0--0--0--0--0--0--0-==========-1--1--1--1--1--1--1--1 1
0. 1
(Plasma Flow) -------->    xxxxxxx (x =B Magnetic Field)
0.   xxxxxxx 1
0. 1
--0--0--0--0--0--0--0--==========-1--1--1--1--1--1--1--1 1
        Electrode

The problem is very simplificated of course. My boundary conditions are the ones showed in the schecth. So my function U goes from 0 to 1, and in the electrodes i put a function so U can be satisfied; and inside the channel, the classic equation of finite difference. I can obtain the current patern but my quention is: How can i introduce the effect of the magnetic field inside the channel?. I was thinking in introducing some Neumann conditions in those points, so the gradient of the funtions varies in order to "simulate" the force of the magnetic field.
 
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  • #2
Is this the right way to do it? Yes, this is the right way to do it. The Neumann boundary condition you introduce will effectively "simulate" the effect of the magnetic field. Specifically, the magnetic field will cause the gradient of the function to increase or decrease in certain areas depending on the direction and strength of the field. You can also model the effect of the magnetic field more accurately by introducing additional terms into your finite difference equation that account for the force of the magnetic field.
 

1. What are boundary conditions in the context of Laplace equations?

Boundary conditions in the context of Laplace equations are constraints that are applied to the solution of the equation at the boundaries of the problem domain. These constraints help determine the unique solution to the equation and are essential for solving the problem accurately.

2. What are the types of boundary conditions in Laplace equations?

The types of boundary conditions in Laplace equations include: Dirichlet boundary conditions, Neumann boundary conditions, and mixed boundary conditions. Dirichlet conditions specify the value of the solution at the boundary, Neumann conditions specify the derivative of the solution at the boundary, and mixed conditions are a combination of both.

3. How do boundary conditions affect the solution of Laplace equations?

Boundary conditions are crucial in determining the unique solution to Laplace equations. They restrict the range of possible solutions and help obtain a well-posed problem. Without proper boundary conditions, the solution may not be unique or physically meaningful.

4. Can boundary conditions be applied at any point in the problem domain?

No, boundary conditions can only be applied at the boundaries of the problem domain. This is because the boundary conditions represent the behavior of the solution at the boundaries, and it is not possible to specify the behavior at points within the domain.

5. How do you choose the appropriate boundary conditions for a Laplace equation problem?

The appropriate boundary conditions for a Laplace equation problem depend on the physical problem being modeled. It is essential to understand the behavior of the solution at the boundaries and choose boundary conditions that reflect this behavior accurately. It may also be necessary to consult with experts in the field or conduct experiments to determine the appropriate boundary conditions.

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