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-   -   Laminar , steady state pipe flow (http://www.cfd-online.com/Forums/openfoam/65640-laminar-steady-state-pipe-flow.html)

andesameer June 22, 2009 04:36

Laminar , steady state pipe flow
 
I would like to solve steady state, laminar flow of newtonian fluid in cylindrical pipe. Can you please suggest which solver would be more appropriate.

Thank a lot

Sam

sudhar June 22, 2009 21:55

laminar solver
 
hi sam ,
the simple and the most basic solver for a laminar and incompressible flow is icoFoam.

andesameer June 22, 2009 23:16

Hi Sudharshan,

Thank you for your reply.

icofoam solver solves transient, laminar and incompressible newtonian flow. But I am looking to solve for steady state, laminar and incompressible newtonian flow.

Can I use simplefoam to solve laminar flow by changing code?

santos June 23, 2009 04:30

Hi,

To use simpleFoam for laminar flow, you have to edit constant/RASProperties of your case and change RASModel to laminar.

Regards,
Jose Santos

sven June 23, 2009 13:36

You can also use icoFoam. Although the solver is transient, you will get an steady-state solution after some time, since the flow itself becomes steady-state. as far as I know, a steady-state solver does exactly the same, it solves the equations with the time derivatives and the solution proceeds in time until a steady-state is reached. I did this for a rectangular channel flow and it worked well.

sudhar June 24, 2009 21:57

hi sam,
you can use simpleFoam for your case but need to edit RAS properties before using. Good luck.

regards,
sudharsan

andesameer June 24, 2009 23:04

Thank you to all.

I will solve the my problem using simplefoam. I will let u know if I face any difficulty.

Thank you.
Sam

Goutam March 15, 2012 10:57

Quote:

Originally Posted by andesameer (Post 220401)
Thank you to all.

I will solve the my problem using simplefoam. I will let u know if I face any difficulty.

Thank you.
Sam

Dear Sam

I am trying to solve a steady state incompressible laminar flow for a pipe with circular cross section, but I didn't get the fully developed parabolic shape for velocity profile.
I am using simpleFOAM (OF-2.1.0) where I have changed the RAS properties to laminar and set the turbulent off. Could you please suggest me, where is the problem? Do you able to solve this simple problem?

If you give me your email ID, I can send you the files.

Thanks

Goutam

Locky3827 March 15, 2012 18:24

Hi Sam,
I have used icoFoam for this problem and nonNewtonianicoFoam for the corresponding non-Newtonian case. Both work very well, it is also easy to cross check with the analytical values.
Regards,
Lachlan

skyinventorbt March 16, 2012 00:38

switch off turbulence , use laminar in the RAS file of /const floder

nandiganavishal March 27, 2013 10:53

Hi,

I would like to know, if it is possible to solve a laminar flow in a cylindrical pipe using 2d simulations in openfoam. If so, please can anyone let me know, how to construct the geometry. Further, should we change anything in the icoFoam solver.

Thanks

Regards
Vishal

skyinventorbt March 27, 2013 23:46

2D simulations - Reg
 
Dear Nandhigana Vishal,

You can create 2D simulations by considering a wedge shaped geometry as shown in Figure 5.3 in OpenFOAM manual 2.0.0.

For creating wedge refer Figure 5.7 in the same manual.

nandiganavishal March 28, 2013 02:12

Quote:

Originally Posted by skyinventorbt (Post 416870)
Dear Nandhigana Vishal,

You can create 2D simulations by considering a wedge shaped geometry as shown in Figure 5.3 in OpenFOAM manual 2.0.0.

For creating wedge refer Figure 5.7 in the same manual.

Dear Kannan,

Thanks for your reply. I had a chance to go through the manual earlier, but could not exactly follow how the geometry and boundary conditions are incorporated using the wedge BC. For instance, I would like to create a cylinder of length 8 m and diameter 0.1 m. The inlet of the cylinder has a uniform velocity and the walls have no slip. How do we create this geometry and what angle should be specified for the wedge. Can you please illustrate this with an example along with the patch definitions.

Thanks for the help

Vishal

skyinventorbt March 28, 2013 07:15

Simple solution
 
Dear Vishal,

  1. Create an wedge (Angle of 5 Degree). Simply a hex collapsed to form a wedge as shown in manual.
  2. Axis is type empty
  3. Front and back face type wedge
  4. For velocity use type uniform and fixed value
Go through Cavity and pitzdaily examples in OpenFOAM tutorial once for understanding and kindly follow the above.
Of course you will find difficulty. But try once then you will get it.

nandiganavishal April 1, 2013 00:57

Quote:

Originally Posted by skyinventorbt (Post 416936)
Dear Vishal,

  1. Create an wedge (Angle of 5 Degree). Simply a hex collapsed to form a wedge as shown in manual.
  2. Axis is type empty
  3. Front and back face type wedge
  4. For velocity use type uniform and fixed value
Go through Cavity and pitzdaily examples in OpenFOAM tutorial once for understanding and kindly follow the above.
Of course you will find difficulty. But try once then you will get it.

Hi Kannan,

Thanks for your reply. I got an understanding on the geometry construction for a simple cylinder. However, I would like to construct a concentric pipe type geometry. I would like to know if the same angle (=5 degree) should be specified for the inner cylinder too. In the manual, it says the angle should be less than 5 degrees to construct 2d axis symmetric cylinder type geometries. Could you explain why this should be the case.

Thanks

Regards
Vishal

skyinventorbt April 1, 2013 07:19

Dear Vishal,

For 2D simulations we must have one cell thickness for FVM. I guess this may be the reason (or) OpenFOAM defines 2D when the angle is less than 5 degrees with one cell in thickness.

nandiganavishal April 1, 2013 18:57

1 Attachment(s)
Quote:

Originally Posted by skyinventorbt (Post 417541)
Dear Vishal,

For 2D simulations we must have one cell thickness for FVM. I guess this may be the reason (or) OpenFOAM defines 2D when the angle is less than 5 degrees with one cell in thickness.

Hi Kannan,

Thanks for the reply. I have constructed the wedge geometry for a simple laminar pipe flow.

I wanted to simulate a laminar flow with inlet velocty = 1m/s in a cylindrical pipe of Diameter = 0.2 m and length = 8 m. I have considered kinematic viscosity = 2e-3 Pa.s and density = 1kg/m^3.

I have tried using both SimpleFoam (switching off turbulence) and icoFoam. However, the code does not converge. I am attaching the files. Please let me know, if the geometry construction is accurate, considered (theta = 5 degree).

Thanks

Regards
Vishal

skyinventorbt April 2, 2013 00:03

Dear Vishal,
The geometry is fine but there are errors in grid. Kindly check the mesh using ""checkMesh"" and correct it. What I found is
***Number of non-orthogonality errors: 19800.
***Error in face pyramids: 59900 faces are incorrectly oriented.
Failed 2 mesh checks.


Kindly correct these errors and submit the grid for solution.

nandiganavishal April 2, 2013 01:12

Quote:

Originally Posted by skyinventorbt (Post 417731)
Dear Vishal,
The geometry is fine but there are errors in grid. Kindly check the mesh using ""checkMesh"" and correct it. What I found is
***Number of non-orthogonality errors: 19800.
***Error in face pyramids: 59900 faces are incorrectly oriented.
Failed 2 mesh checks.


Kindly correct these errors and submit the grid for solution.


Thanks, very much Kannan. I found the bug. I had changed the direction of z axis in my new blockMesh file and that did the trick. Now the solver works. I would now like to check the solution and would then move on to making a concentric pipe geometry. Is there anything I should make a note of while constructing the concentric pipe geometry. Let me know.

Thanks

Vishal

nandiganavishal April 2, 2013 13:22

Quote:

Originally Posted by nandiganavishal (Post 417737)
Thanks, very much Kannan. I found the bug. I had changed the direction of z axis in my new blockMesh file and that did the trick. Now the solver works. I would now like to check the solution and would then move on to making a concentric pipe geometry. Is there anything I should make a note of while constructing the concentric pipe geometry. Let me know.

Thanks

Vishal

Hi Kannan,

As we have created a wedge whose faces are not aligned to the cooridnate plane. So the maximum height in the radial direction now corresponds to (r*cos(theta/2)) and not exactly "r". Should we rescale the values obtained for the velocity and pressure in the radial direction ? Please let me know.

Thanks

Regards
Vishal


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