partial differential equation

Thread Starter

jav_dec80

Joined Oct 6, 2013
2
Good morning

Please help me to solve
Ut = 3Uxx 0 < x < 2 and t > 0
Ux(0 , t ) = Ux( 2 , t ) = o
U (x , 0 ) = 3x

Thanks
 

blah2222

Joined May 3, 2010
582
Good morning

Please help me to solve
Ut = 3Uxx 0 < x < 2 and t > 0
Ux(0 , t ) = Ux( 2 , t ) = o
U (x , 0 ) = 3x

Thanks
Is your goal to solve this analytically on paper or are you able to use numerical methods such as finite difference in MATLAB?

Tidying things up, is this what you're given?

0 < x < 2 & t > 0

\(
\frac{\partial u}{\partial t} = 3\frac{\partial^{2} u}{\partial x^{2}}
\)

\(
\frac{\partial u}{\partial x}(0, t) = \frac{\partial u}{\partial x}(2, t) = 0
\)

\(
u(x, 0) = 3x
\)
 

WBahn

Joined Mar 31, 2012
33,009
It's been many moons since I solved PDEs. My first (feeble) thought would be to assume an exponential form of a solution and see what that does.
 
The PDE is a well-known PDE: the heat equation or the diffusion equation. There most common solution and can be derived assuming the solution u(x,t) = X(x)T(t). The the other analytical solution involves the complementary error function. I suspect it involves Laplace/Fourier Transforms. However, the latter solution holds only for boundary conditions of 0 at x = +- infinity and intial conditions of a delta function. So this probably leaves the former as the likely solution which you will find is a Fourier series involving only cos(x) functions due to the boundary condition.

See this: http://en.wikipedia.org/wiki/Parabolic_partial_differential_equation
 
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