1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Log transform on cylindrical coordinates

  1. Nov 4, 2012 #1
    1. The problem statement, all variables and given/known data
    I'd like to do a log transform on the radius variable of the heat conservation equation:

    qr - qr + Δr= ΔE/Δt

    where qr= -kA(dT/dr)

    My solution for this equation in cylindrical coordinates is:

    Tt+Δt=Tt+(Δt*k)/(ρ*c*Δr^2)* [(Tt-1-Tt)/(ln(rt/rt-1) - (Tt-Tt+1)/(ln(rt+1/rt)]

    3. The attempt at a solution

    I've written a matlab program with this transient eq. and I'd like to be able to have r be logarithmic so that there are a lot of radius nodes for small radii and less for more distant radii.

    dT/dlog(r) = r * dT/dr?

    qr = -k(A)r dT/dr?

    how can I log transform the transient eq for heat conservation? I've been struggling with this..
    Last edited: Nov 4, 2012
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted