﻿ Sample Problems > Usage > 1D > 1d_cylinder_transient

# 1d_cylinder_transient

Navigation:  Sample Problems > Usage > 1D >

# 1d_cylinder_transient

{ 1D_CYLINDER_TRANSIENT.PDE

This problem analyzes the diffusive loss of a solute from a solvent due to leakage

across an outer boundary using 1D cylindrical coordinates.

}

title '1D time dependent diffusion in a Cylinder'

coordinates

cylinder1("R")

variables

C

definitions

D = 1

source = 0

b = 1

a = 2

C0 = 10

diss = 0.01     ! dissolution coefficient

Cext = 0       ! external sink concentration

Flux = -D*dr(C)

initial values

C = C0

equations

C: div(D*grad(C)) + source = dt(C)

boundaries

region 1

start (b)   point load(C)=0

line to (a) point load(C)=diss*(Cext-C) !outer leakage rate

time 0 to 10

monitors

for cycle=1

elevation(C) from (b) to (a)

plots

for cycle=10

elevation(C) from (b) to (a)

elevation(Flux) from (b) to (a) range=(0,0.01) {minimum plot range}

history(C) at (b) ((b+a)/2) (a)

history(Flux) at (b) ((b+a)/2) (a)

end