Questions tagged [heat-equation]

For questions related to the solution and analysis of the heat equation.

The heat equation is a particular parabolic partial differential equation used to describe the temperature or heat distribution of a system over time. It can be written most generally as

$$\frac{\partial u}{\partial t} - \alpha \nabla^2 u = 0$$

where $\nabla^2$ is the Laplace operator, and $\alpha$ is a positive constant describing thermal diffusivity (which is usually normalized to $1$).

There are a number of common solution techniques, including separation of variables and Fourier series, as well as using a Green's function to find a fundamental solution.

Reference: Heat equation.

1607 questions
0
votes
0 answers

Solving a diffusion problem

I have to the following diffusion problem , which is given by the one-dimensional diffusion equation: \begin{equation} \frac{d^2}{dx^2}f=\frac{1}{a^2}\frac{d}{dt}f \end{equation} It is given that the diffusion constant is $1/4$, so I take that is…
Luthier415Hz
  • 2,739
  • 6
  • 22
0
votes
0 answers

Is the heat equation (e.g. 2D) solvable without boundary conditions? Or are the boundary conditions always present?

Is the heat equation (e.g. 2D) solvable without boundary conditions? Or are the boundary conditions always present? I've been puzzled a bit, since it seems that w/o boundary conditions there's no evolution from initial state. But this is what I'm…
mavavilj
  • 7,270
0
votes
0 answers

help in Solving PDE heat problem with FFCT

solve the following heat problem using Finite Fourier Coseine Transform(FFCT): A metal bar of length $L$, is at constant temperature of $U0$, at $t=0$ the end $x=L$ is suddenly given the constant temperature of $U_1$ and the end $x=0$ is insulated.…
aows61
  • 13
0
votes
0 answers

I need to show that a specific function fulfills $u_t+u_{xx}/2=0$ (the heat equation).

I want to show that \begin{gather} u(x,t) = \int_0^\infty \frac{f(t+s)}{\sqrt{2\pi s^3}}\sum_{n=-\infty}^\infty \left[(4n+1-x)exp\left(-\frac{(4n+1-x)^2}{2s}\right)+(4n+1+x)exp\left(-\frac{(4n+1+x)^2}{2s}\right)\right]ds\\ \text{with}\quad…
0
votes
1 answer

Heat equation and boundary conditions

I am reading about the one dimensional heat equation and boundary conditions. This is what the author writes about the left hand end of the rod: Can someone explain to me why the slope must be positive at $x=0$? If the rod is hotter shouldn't it…
0
votes
1 answer

Verifying inhomogeneous solution of heat equation.

Here is my question. How (3.21) is induced? I tried several times but I could not get the answer.
Harold
  • 1
0
votes
1 answer

Equation of heat conduction for spherical solid

What will be the correct Equation of heat conduction for a homogeneous spherical solid with constant thermal diffusivity K and no heat source?
-1
votes
1 answer

Nonhomogenous 2D heat equation

We have the following system that describes the heat conduction in a rectangular region: $$\begin{cases} u_{xx}+u_{yy}+S=u_t \\ u(a,y,t)=0 \\ u_x(x,b,t)=0 \\ u_y(0,y,t)=0 \\ u(x,0,t) = 0 \\ u(x,y,0) = f(x,y) \end{cases} $$ $S$ is source term…
1 2
3