# NS equations

1. Nov 28, 2015

### pasta

Can somebody provide a solution for this question?
convert 3 dimensional unsteady compressible NS equations to axisymmetric 2 dimensional incompressible laminar form for a cylindrical pipe, then make a derivation of streamwise velocity profile u(r) using the appropriate boundary conds.

thanks

2. Nov 28, 2015

### BvU

Helllo pasta,

Unfortunately (in first order) this is not the way PF works. You can get expert help but you have to make an effort yourself as well: read the guidelines and use the template; then we can help you.

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution​

3. Nov 28, 2015

### pasta

• This homework problem was originally posted in another forum so there is no template
use cylindrical coordinates equations
zero out all of the transient terms, take the limit as the density goes to a constant and div U goes to zero.
mass equation will collapse to div U = 0

once ive calncelled. what do i do?

4. Nov 29, 2015

### bigfooted

Can you share the equation that you have derived? Then we can help you point out where it went wrong or help you on the next step.

5. Nov 29, 2015

### Staff: Mentor

Which velocity components are zero, and which velocity components are not zero? Take that into account. What about the acceleration terms? Is the flow accelerating? What about the boundary conditions on velocity? What is the velocity at the wall?

Chet