PDE propagating from point source
4 次查看(过去 30 天)
显示 更早的评论
I want to solve numerically a nonlinear diffusion equation from an instantaneous point source. Thus, I have initial conditions, but not boundary conditions. How should I go about writing a code to solve circular propagation from a point?
Thanks!!
2 个评论
Torsten
2015-7-13
What is the equation you try to solve (because you are talking about a nonlinear diffusion equation) ?
Best wishes
Torsten
采纳的回答
Torsten
2015-7-14
I assume you want the point source appear at r=0.
Choose the interval of integration as [0:R] where R is big enough to ensure that C=C(t=0) throughout the period of integration.
As initial condition, choose an approximation to the delta function.
As boundary conditions, choose dC/dr = 0 at both ends.
Best wishes
Torsten.
6 个评论
Torsten
2015-7-27
1. You will have to work with a numerical approximation to the delta function. I gave you a suitable link.
2. Your boundary conditions are incorrect. You will have to set
pl=0, ql=1, pr=0, qr=1
3. I don't understand your definition of D. The setting
D = D_0/(KronD(r, 0))^n;
doesn't make sense.
Best wishes
Torsten.
Nicholas Mikolajewicz
2018-2-2
Torsten, regarding the earlier answer you provided, whats the reasoning behind using the dirac delta approximation for the point source rather than just setting the initial condition to the source concentration/density as u0(x==0) = initial condition?
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Eigenvalue Problems 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!