Logo
Pattern

Discover published sets by community

Explore tens of thousands of sets crafted by our community.

Finite Difference Method for PDEs

10

Flashcards

0/10

Still learning
StarStarStarStar

Heat equation: utα2ux2=0\frac{\partial u}{\partial t} - \alpha \frac{\partial^2 u}{\partial x^2} = 0, u(0,t)=u(L,t)=0u(0, t) = u(L, t) = 0, u(x,0)=f(x)u(x, 0) = f(x)

StarStarStarStar

Discretize time and space using a grid. Apply explicit or implicit methods to approximate u(x,t)u(x,t). Stability and convergence are based on the chosen time and space step sizes.

StarStarStarStar

Poisson's equation: 2u=f(x,y)-\nabla^2 u = f(x,y), with Dirichlet boundary conditions

StarStarStarStar

Create a grid over the domain, and use a finite difference approximation for the Laplacian. Solve the resulting linear system for u(x,y)u(x,y).

StarStarStarStar

Burgers' equation: ut+uux=ν2ux2\frac{\partial u}{\partial t} + u\frac{\partial u}{\partial x} = \nu\frac{\partial^2 u}{\partial x^2}, u(0,t)=u(L,t)=0u(0,t)=u(L,t)=0, u(x,0)=f(x)u(x, 0) = f(x)

StarStarStarStar

A combined hyperbolic and parabolic PDE. Use finite differences for time and space, applying explicit/implicit methods and a nonlinear solver for the convective term.

StarStarStarStar

Diffusion equation with variable coefficients: ut=(D(x,y)u)\frac{\partial u}{\partial t} = \nabla\cdot(D(x,y)\nabla u), with mixed boundary conditions

StarStarStarStar

Use finite differences for spatial discretization. Handle variable D(x,y)D(x,y) by averaging at cell edges and apply an appropriate time-stepping method.

StarStarStarStar

Wave equation: 2ut2=c22ux2\frac{\partial^2 u}{\partial t^2} = c^2 \frac{\partial^2 u}{\partial x^2}, u(0,t)=u(L,t)=0u(0, t) = u(L, t) = 0, u(x,0)=g(x)u(x, 0) = g(x), ut(x,0)=h(x)\frac{\partial u}{\partial t}(x, 0) = h(x)

StarStarStarStar

Use a central difference approximation for both time and space. Solve for the wave height at each time step, ensuring stability with proper step sizes.

StarStarStarStar

Laplace's equation: 2u=0\nabla^2 u = 0, with Neumann boundary conditions

StarStarStarStar

Construct a grid and replace the Laplacian with a finite difference counterpart. The Neumann conditions imply derivatives on boundaries, adjust the finite differences accordingly.

StarStarStarStar

Convection-diffusion equation: ut+vu=κ2u\frac{\partial u}{\partial t} + \vec{v} \cdot \nabla u = \kappa \nabla^2 u, with Dirichlet and Neumann boundary conditions

StarStarStarStar

Discretize the domain and apply finite difference to both convection and diffusion terms. Use a mixed approach for boundary conditions, applying Dirichlet and Neumann as specified.

StarStarStarStar

Nonlinear Schrödinger equation: iΨt=122Ψ+V(x)Ψ+gΨ2Ψi\frac{\partial \Psi}{\partial t} = -\frac{1}{2}\nabla^2 \Psi + V(x)\Psi + g|\Psi|^2\Psi, with absorbing boundary conditions

StarStarStarStar

Grid the space-time domain, discretize the Laplacian and nonlinear terms, and apply an appropriate method to deal with absorption at the boundaries.

StarStarStarStar

Advection equation: ut+cux=0\frac{\partial u}{\partial t} + c \frac{\partial u}{\partial x} = 0, with periodic boundary conditions

StarStarStarStar

Use a temporal and spatial discretization. For periodic boundaries, wrap the ends of the domain. Upwind schemes can help with stability.

StarStarStarStar

Telegraph equation: 2ut2+aut=c22ux2\frac{\partial^2 u}{\partial t^2} + a\frac{\partial u}{\partial t} = c^2 \frac{\partial^2 u}{\partial x^2}, with fixed endpoints

StarStarStarStar

Discretize time and space. Use a time-stepping scheme that handles the second derivative in time, and apply boundary conditions to the spatial discretization.

Know
0
Still learning
Click to flip
Know
0
Logo

© Hypatia.Tech. 2024 All rights reserved.