
#1
Jul1404, 10:01 AM

Sci Advisor
PF Gold
P: 1,481

Hi guys. I am solving the axisymmetric free jet of an incompressible fluid. But I have troubles at r=0. Continuty equation can be written in cylindrical coordinates as:
1/r*d(rv)/dr + du/dz=0 v=radial velocity (v=0 at r=0) u=axial velocity. hz=delta(z) hr=delta(r) What happens at r=0?. I have to obtain a finite difference scheme in order to integrate the problem, so I have created a grid that has "i" index for "z" coordinate and "j" index for "r" coordinate. j=1 corresponds to the simmetry axe. for j>1 I have no problem because r>0. But in r=0 there is a singularity point. How can I deal with this?. As you can see I know v(i,1)=0 



#2
Jul2304, 08:04 AM

P: 3

1/r*d(vr)/dr+du/dz=0 =>
1/r*(v+r*dv/dr)+du/dz = v/r + dv/dr +du/dz at r=0, v=0 > dv/dr + du/dz = 0 does this help? 


Register to reply 
Related Discussions  
continuity equation  Introductory Physics Homework  6  
Deriving the continuity equation from the Dirac equation (Relativistic Quantum)  Advanced Physics Homework  3  
Equation of continuity  Advanced Physics Homework  1  
Continuity Equation  Introductory Physics Homework  11  
Why is the continuity equation called the continuity equation?  General Physics  1 