# Pressure drop in openfoam

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 June 6, 2013, 14:01 Pressure drop in openfoam #1 New Member   Join Date: Feb 2013 Posts: 6 Rep Power: 12 Good evening, i am new here and this is my first post. I would like to simulate a pressure drop in a flow but i dont really know how to do it I've tried to do that with a fan like in the tutorial TJunctionFan. So combine tjunction and pitzDaily, but i do not really understand what the patches the baffles abd so on is...( i still red a lot on the openfoam website an on the web, but nothing is clearly explained) So i tried another solution, i tried to do my own solver with my own geometry but its remains very complicate... How can i work efficiently with openfoam, what are the first things to know before starting with my simulation thank you Leden...

 June 6, 2013, 18:53 #2 Senior Member   Lieven Join Date: Dec 2011 Location: Leuven, Belgium Posts: 299 Rep Power: 21 Hi Ledeniso, Welcome to the forum! First of all, can you give a little bit more information about your case? A few things that immediately cross my mind: * incompressible/compressible * laminar/turbulent * isothermal? * Why would you need your 'own solver'? * What do you mean exactly by 'work efficiently with OF'? I can give you a lot of advice, but the best place to start is here: http://ae.metu.edu.tr/tuncer/bookmarks/cfdnottodo.pdf Cheers, Lieven HappyS5 likes this.

 June 6, 2013, 19:18 #3 New Member   Join Date: Feb 2013 Posts: 6 Rep Power: 12 thanks to you Lieven, my case consist to simulate a flow throught a porous wall in the middle of the flow. my first idea was to simulate a flow in a pipe with a pressure drop where the porous wall has to be. In order to reach that goal, ilooked for tutorials which match at the best to my case, but all the tutorial are so various and complicate to understand and so on... To simulate a pressure drop in a flow i choose the case TJunctionFan ( with the fan to decrese my pressure, to simulate the flow, i choose the pitzDaily case flow. So the goal was to combine Tjunction with pitzDaily, but it's doesn"t work at all, i have tried a lot of solution without succes. That's why i through perhaps it's better to create my own solver with all the boundary condition i need, but it seems to be mission impossible How can i lose problem in Openfoam, do i do this with the tutorials given while the installation? the flow is laminar and incompressible. Thanks again for your answers and sorry for my english. Leden...

 June 7, 2013, 10:35 #4 Senior Member   Lieven Join Date: Dec 2011 Location: Leuven, Belgium Posts: 299 Rep Power: 21 Hi Leden, Why don't you start from the porousSimpleFoam solver? Regarding the tutorials, don't expect to be able to learn to work with openfoam and all it's applications/tools/tricks/... in a few weeks. That's just not possible for any normal human being. First go through the tutorials explained in the manual, afterwards switch to the one closest to the case you want to simulate. My apologies, but I don't understand the sentence "How can i lose problem in Openfoam, do i do this with the tutorials given while the installation?" Cheers, Lieven

 June 10, 2013, 03:23 Hi lieven #5 New Member   Join Date: Feb 2013 Posts: 6 Rep Power: 12 I'm going to start learn about the porousSimpleFoam solver this week, and i will try like you advised it to me, to modify it in order to have something that matchs with my case. with the sentence, i mean are the tutorials the only way to lose problems in OpenFOAM or does it exist anys else tutorial to learn more about OpenFOAM? I am thanking you so much for your anszer, and i will inform you of my advance. Leden...

 June 10, 2013, 12:59 #6 Senior Member   Lieven Join Date: Dec 2011 Location: Leuven, Belgium Posts: 299 Rep Power: 21 Hi Ledeniso, I think the tutorials are the best place to start. If you search the web or this forum a bit, you can find some additional ones. Depending on how far you need to go, you can also search for 'programming tutorials'. And this forum is definitely also a huge source of input for new OpenFOAM users (and also for the more experienced ones ;-)). Of course, there are also the OpenFOAM training sessions organized by ESI but I have no experience with those. Cheers, Lieven

 July 16, 2013, 03:52 #7 New Member   Mohammad Join Date: Jul 2013 Posts: 10 Rep Power: 11 Hi dear Foamers, I would be grateful if you could help me in my problem. I am new to OF, so forgive me for my simple questions which may seem absolutely trivial to you. I want to model a 2D channel in which the driving force is pressure gradient. Sounds simple, but I do not know how to do it. I want to use cyclic BC for both U and P. I studied about cyclic and fan BC and other stuff. I could solve the problem with cyclic BC for both U and P while the upper wall is moving (like cavity problem), and I used icoFoam. But I do not know how to do it for pressure gradient case? what solver shall I use? I know in the forum people said that channelFoam is a good one, but you know that in OF2.2.1 it is removed. shall I use pimpleFoam? or simpleFoam? or icofoam? please notice that my flow is laminar. How may I apply the pressure gradient? How may I apply the cyclic BC? Thank so much for your time. Mohammad

 July 17, 2013, 08:38 #8 Senior Member   Lieven Join Date: Dec 2011 Location: Leuven, Belgium Posts: 299 Rep Power: 21 Hi Mohammad, You can use the fvOptions of OpenFOAM 2.2.x named pressureGradientExplicitSource. This replaces the functionallity of the channelFoam solver (hence it is removed from OF 2.2). As far as I understand, you can use this in combination with any of your preferred solvers. If your flow is laminar, icoFoam or pisoFoam will do the trick. Applying the cyclic BC is really simple, just set the boundary conditions of the corresponding patches to 'cyclic' for all of the variables. Hope this clarifies this, if I forgot the mention something, just ask again :-). Cheers, Lieven

 August 31, 2018, 05:42 pressure drop #9 New Member   pelin ilker Join Date: Jun 2018 Posts: 2 Rep Power: 0 Hello all, I am new at OF and I have a problem with modeling pressure drop of a laminar flow in a pipe, I used icoFoam, it worked but I don't know how I obtain the pressure drop value? Thanks

March 21, 2019, 04:08
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Josh Williams
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Quote:
 Originally Posted by pelinilker Hello all, I am new at OF and I have a problem with modeling pressure drop of a laminar flow in a pipe, I used icoFoam, it worked but I don't know how I obtain the pressure drop value? Thanks
did you find the solution to this?

March 21, 2019, 10:49
#11
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Join Date: Jan 2014
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Quote:
 Originally Posted by pelinilker Hello all, I am new at OF and I have a problem with modeling pressure drop of a laminar flow in a pipe, I used icoFoam, it worked but I don't know how I obtain the pressure drop value? Thanks
jsut search for "pressureDifferencePatch OpenFOAM" or just do it by your own using Paraview. Therefore examine the mass flow area averaged or just the surface area averaged static pressure for your inlet and outlet and subtract them.

 August 16, 2019, 07:44 Pressure drop in openfoam #12 New Member   Join Date: Aug 2019 Posts: 19 Rep Power: 5 Hello all, Just came across an issue in rhoSimpleFoam solver. My simulation is a simple pipe with an obstacle that introduces a pressure drop in the laminar flow. OpenFoam does not calculate the pressure drop, can anyone help me? Thanks in advance, Didu

 August 16, 2019, 07:48 #13 New Member   Join Date: Aug 2019 Posts: 19 Rep Power: 5 Hello all, Just came across an issue in rhoSimpleFoam solver. My simulation is a simple pipe with an obstacle that introduces a pressure drop in the laminar flow. OpenFoam does not calculate the pressure drop, can anyone help me? Thanks in advance, Didu

 August 16, 2019, 08:35 #14 Member     Ingo Riess Join Date: Jun 2019 Location: Switzerland Posts: 40 Rep Power: 5 Code: ```Application rhoSimpleFoam Group grpCompressibleSolvers Description Steady-state solver for compressible turbulent flow.``` Maybe, you did not select the correct solver, maybe you don't resolve the near-wall shear stress correctly, maybe... it is hard to answer as we cannot guess what you are doing.

 August 16, 2019, 09:16 #15 New Member   Join Date: Aug 2019 Posts: 19 Rep Power: 5 Hi Ingo, Thank you for your reply, I'm simulating a laminar flow, steady state, a geometry of a cylinder, and in the middle there is an obstacle, what is the best solver, in your opinion? Thanks in advance

 August 19, 2019, 04:29 #16 Member     Ingo Riess Join Date: Jun 2019 Location: Switzerland Posts: 40 Rep Power: 5 If your flow is laminar, you may well assume it is incompressible. Then I would use icoFoam (transient). As you have a pipe geometry with an obstacle, I would start with the tutorial "elbow". You will have to generate your own mesh and adapt the boundary conditions to match your flow problem.

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