CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Pressure in solidDisplacementFoam

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   March 7, 2016, 15:44
Default Pressure in solidDisplacementFoam
  #1
Member
 
Ruggero Poletto
Join Date: Nov 2013
Posts: 31
Rep Power: 5
rupole1185 is on a distinguished road
Is it correct this in the D file:

wall_name
{
type tractionDisplacement;
traction uniform ( 0 0 0 );
pressure uniform 600000;
value uniform (0 0 0);
}

Application of the pressure that act of a particular wall?
rupole1185 is offline   Reply With Quote

Old   March 8, 2016, 06:52
Default
  #2
Senior Member
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin,Ireland
Posts: 626
Rep Power: 22
bigphil will become famous soon enoughbigphil will become famous soon enough
Quote:
Originally Posted by rupole1185 View Post
Is it correct this in the D file:

wall_name
{
type tractionDisplacement;
traction uniform ( 0 0 0 );
pressure uniform 600000;
value uniform (0 0 0);
}

Application of the pressure that act of a particular wall?
Yes, this will apply a surface pressure of 0.6 MPa to the wall.
The surface pressure is: Tn = -n & (n & sigma),
where 'n' is the surface unit normals and 'sigma' is the stress tensor.

Philip
bigphil is offline   Reply With Quote

Old   March 8, 2016, 08:25
Default
  #3
Member
 
Ruggero Poletto
Join Date: Nov 2013
Posts: 31
Rep Power: 5
rupole1185 is on a distinguished road
Thanks a lot for your reply!
__________________
___________________________

President of CONSELF, the new CFD company with a great cloud solution. Try for free it here!
rupole1185 is offline   Reply With Quote

Old   October 15, 2016, 15:48
Default tractionDisplacement | meaning of "value (0 0 0)"?
  #4
New Member
 
tomdylan's Avatar
 
Tom Dylan
Join Date: May 2015
Posts: 10
Rep Power: 3
tomdylan is on a distinguished road
Quote:
Originally Posted by bigphil View Post
Yes, this will apply a surface pressure of 0.6 MPa to the wall.
The surface pressure is: Tn = -n & (n & sigma),
where 'n' is the surface unit normals and 'sigma' is the stress tensor.

Philip
Could you kindly explain the third parameter vector "value (0 0 0)"?

Does it have to do something with a pressure gradient?

My problem consists of pressure variations on a vertical (or inclined) wall in response to water level fluctuations. In that case the pressure has a hydrostatic vertical distribution. I am seeking the right boundary condition for such a case.

Any hints warmly appreciated!

Tom
tomdylan is offline   Reply With Quote

Old   October 15, 2016, 16:22
Default
  #5
Member
 
Ruggero Poletto
Join Date: Nov 2013
Posts: 31
Rep Power: 5
rupole1185 is on a distinguished road
Quote:
Originally Posted by tomdylan View Post
Could you kindly explain the third parameter vector "value (0 0 0)"?

Does it have to do something with a pressure gradient?

My problem consists of pressure variations on a vertical (or inclined) wall in response to water level fluctuations. In that case the pressure has a hydrostatic vertical distribution. I am seeking the right boundary condition for such a case.

Any hints warmly appreciated!

Tom
No the third term is just a common thing in openfoam. It's the variable value on the surface (I.e. the displacement is zero at first iteration)
__________________
___________________________

President of CONSELF, the new CFD company with a great cloud solution. Try for free it here!
rupole1185 is offline   Reply With Quote

Old   October 16, 2016, 17:26
Default
  #6
Senior Member
 
bigphil's Avatar
 
Philip Cardiff
Join Date: Mar 2009
Location: Dublin,Ireland
Posts: 626
Rep Power: 22
bigphil will become famous soon enoughbigphil will become famous soon enough
Quote:
Originally Posted by rupole1185 View Post
No the third term is just a common thing in openfoam. It's the variable value on the surface (I.e. the displacement is zero at first iteration)
Hi Tom,

To add to the previous comment, I noticed from the other thread that you are interested in poro-elasticity; you should be careful to not to confuse the pore-pressure with the "pressure" in the solidTraction boundary condition, which is the normal component of the effective traction (or total traction depending on your particular implementation).

Philip
bigphil is offline   Reply With Quote

Old   October 26, 2016, 11:49
Default time varying tractionBC in response to hydrostatic fluctuations
  #7
New Member
 
tomdylan's Avatar
 
Tom Dylan
Join Date: May 2015
Posts: 10
Rep Power: 3
tomdylan is on a distinguished road
Dear Foamers,

first, Philip, let me thank you again for your clarification on the difference between pore-pressure and pressure. to be honest I was at first sight a little bit confused but after a while I got things clear.

Allow me to present some pictures to illustrate the analysis I am into right now. I want to apply a representative (in respect to the water level in the chamber) tractionBC on a vertical (or inclined) soil boundary patch.



At the present I am not considering the rigid gravity wall structure of
the ship lock, since I have not managed to deal with heterogeneity/multiregions.

As you can figure out form the pictures the filling and emptying of the chamber (more the 6 m head difference)



leads to a time varying hydrostatic pressure distribution along the horizontal sole and the chamber walls. At the bottom the traction BC is straight forward. However I am insecure as to how to represent a time varying traction BC at the vertical (or inclined) boundary patches resulting form a fluctuating hydrostatic pressure in the chamber.

Interestingly, our groundwater measurements in a distance from the lock detected a clear and almost in-phase poroelastic response to the filling and emptying of the chamber in a range of up to 10 kN/m2 (yes the ground can react quite elastic). These head fluctuations are solely induced by stress variations in the chamber.



I guess that I am not the first to deal with head fluctuations and their effect on solid traction and therefore suppose that a solution exists, but currently I have no clue for this kind of problem.

Ana hints warmly appreciated!

Tom
tomdylan is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Pressure loss Velocity coupling CFXMUFFIN CFX 1 February 6, 2016 05:43
Periodic flow using Cyclic - comparison with Fluent nusivares OpenFOAM Running, Solving & CFD 29 November 3, 2015 06:33
Discharge of Pressure Vessel into Pipe with Regulator gajowni2 System Analysis 0 October 31, 2015 19:57
Calculation of the Governing Equations Mihail CFX 7 September 7, 2014 06:27
Unsteady pressure differential between inlet and outlet of the pipe for single phase joshi20h FLUENT 0 September 26, 2012 12:41


All times are GMT -4. The time now is 04:25.