Partial Differential Equation

[neoaspilet11]

Hello every body,

Please help.

Derive the partial differential equation satisfied by the concentration u of a liquid diffusing through a porous solid. Hint: The rate at which liquid diffuses through an area is proportional to the area and to the concentration gradient in the direction perpindicular to the area.

Thanks in advance

 

[steve10]

This is a standard derivation of heat or diffusion equation. Notice that, according to your statement, the rate deltaQ is proportional to du/dn,
deltaQ=-kdu/dn*dS*dt

where the minus sign means that the liquid flows in the opposite direction of the gradient. Based on this, you can mimic any derivation of the heat equation and end up with a heat equation.

 

[papu]

i dont understand ur question ....plzz write ur question is simple way??

 

[alizadeh_m]

There is a wondeful software to solve such equations. it is FLUENT.

 

[maple]

I recommand the FEMLAB.

 

[vlduong]

I recommand the MATHLAB

It's powerful