I'm trying to solve the following partial differential equation:
With the boundary conditions:
I could use another way to resolve this, like the finite volume method, but after I solve the equation I want to manipulate the Dm term and see what happens to the results. The equation is responsible to return the values of humidity in soybeans, and Dm term is the mass diffusion coefficient.
Here's what I've tried:
NDSolve[{
D[m[r, t], t] == 1*10^-7*(D[m[r, t], r, r] + 2/r *D[m[r, t], r]),
m[r, 0] == 0.5,
m[1, t] == 0.2}, m, {t, 0, 5}, {r, 0, 1}]
And it returned:
NDSolve::deqn: Equation or list of equations expected instead of True in the first argument {(m^(0,1))[r,t]==((2 (m^(1,0))[r,t])/r+(m^(2,0))[r,t])/10000000,True,True}. >>
First things first, I'm just trying to solve and plot the PDE with Dm = 1*10 ^-7, and after that I'll try use the function Manipulate to change Dm (Since i haven't been able to solve the equation, I erased the manipulate and plot code, baby steps)
Since I'm a new mathematica user, I don't know what else to do, if anyone could help me I would be grateful!
Clear[m]
and try again. You probably have some left-over downvalues form
, that could have come from doingm = ...
instead ofm == ...
or similar. $\endgroup$m[1,0]
? Boundary condition says it should be 0.2, but initial condition says it's 0.5 $\endgroup$