[udhab619]

I have been assigned the task of discretization of navier stokes equation in cylindrical coordinates in 2-D and writing code for it.please tell me which book or article should I follow to learn the finite volume method easily.

[oky]

Hi everyone,

I need help, how to get the value of convection coefficient [h] from Fluent directly?
Thank you.

Regrads,

Oky

[mina]

hi
i need c++ code simple algoritm, a cylinder with ro radial and adiabatic. a rod with ri radial insert in sylinder and heat flux is constant,Q"=cost, entree temture and velocity are Tin,Vin , Re=500, outer flow development.
i can not conversion cartezian coordenate to cylinderical coordenate and i do not undrestand boundry condition,
i want calculate veocity profile , friction coefficient on outer surface rod and NU number, i should write program with c++;
please help me
thank you very much.

[hilllike]

Hi!
I wrote a 3d code in cylindrical coordinates with FVM.
In staggered gird system, the control cell at the the axis is a triangular cell so that the singularity can be removed.
The only problem is how to calculate the velocity at the axis.

[danial]

Originally Posted by falopsy

I am developing a CFD code for a stirred tank but have quite a few issues I will appreciate if anyone can help me with:

1. There are very few books on the discretisation of the Navier-Stokes equation in cylindrical coordinates. I am having problem knowing which terms to put at the surface and which to put at the centre due to the appearance of terms like 1/r^2.

2. Also, I have issues with staggered grid and I dont really understand the collocated grid methods either. My problem with staggered grid has to do with how to store the velocity vectors as matrices as most program dont accept frational index i.e. vij+1/2 used in staggered grid.

3. Most books have the discretised equation for rectangular coordinate but none for cylindrical coordinates. Is there any good book that explained the discetisation of the Navier-Stokes equation in cylindrical coordinates?

4. I am also thinking maybe I should work in rectangular coordinates but with a cylindrical coordinate fitted grids and then approximate the length of the mesh as rectangular i.e dx=dr, dy = rdTheta, dz= dz. My only concern here is that I need to now convert the source term vectors from rectangular to cylindrical and also my boundary conditions. Does anyone understand what I'm trying to say or does it not make any sense.

Any help will be greatly appreciated. Thanks

i have the same problem like you,i don't know how can discretize Navier stocks equation in cylindrical coordinates.(how integrete them in C.V) i konw it's old post but i really need it

[qutadah.r]

Hello Arjun/everybody


I know this is an old post, however I am running through a similar project, in which i want to code a solver for 3d sonic flow inside a vacuumed cylindrical tube.


I have been thinking of using FVM with cylindrical coordinates, however it would be easier if I just use cartesian. I am thinking how I will apply my boundary conditions, and also since the case involves mass deposition due to cooling at cylinder surface, how will I write the source term in cartesian form? This is my main concern.


Also how will the finite volume look like at the cylinder surface? It will not be uniform by any means.


Also, should I make the surface of the tube as cell center? Or should it be a surface of the finite volume?



If it should be one surface of the finite volume, how will I find the normal vectors to the surface which is the cylinder surface?

To be precise, I will use the flux splitting algorithm at cell interfaces by lax-wendroff coupled with a 5th order WENO reconstruction scheme.



If this wouldn't work, then I will just use cylindrical coordinates in my solver.



Note: I have tried using the non-conservative form of the equations in cylindrical coordinates, with explicit Euler finite differencing scheme and it would not converge, I suppose it is not stable enough and i run into negative densities.


Thanks!


Regards,
Qutadah