Hi, I have a question about cylindrical NS equations. They have 1/r*(r*u) terms, which cannot be disretized at r=0. I am using staggerd 2D axisymmetric cylindrical cordination and would like to give value at r=0. I have tried

--extrapolation

--1/r*(r*u) = (u - (-u))/dr, (axisymmetric) The program runs, but is it OK? Have you got any suggestion?

In the axisymmetric cylindrical NS equations, the radial velocity u is zero at r=0.

L'hospital rule: u/r = du /dr -> (u(i+1)-u(i))/dr +O(dr^2)

Hi

goto : http://ctr.stanford.edu/

then : Publications

Then : annual research brief 2000

Search fo Lele,

The paper is

A new method for accurate treatment of flow equations in cylindrical coordinates using series expansions. G. S. Constantinescu and S. K. Lele

Regards

Apurva

Thank you for your kind reply. My program is almost complete. But I have one more problem.

I know Vz/r = d(Vz)/dr = 0

but what about Vr/r = d(Vr)/r = ??

Which is appropriate? Vr/r = d(Vr)/r = (Vr(1) - 0)/dr or Vr/r = d(Vr)/r = 0