# RhoExplicitPorousSimpleFoam

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 July 30, 2007, 04:36 Hello, I have a question (or #1 Member   Radu Mustata Join Date: Mar 2009 Location: Zaragoza, Spain Posts: 97 Rep Power: 10 Hello, I have a question (or more) about rhoExplicit(Implicit)porousFoam: 1. In specifying e1 and e2 in the porousZones, that gives me the orientation of the resistance "vector", right? 2. How does a given value of K (permeability m**2) and porosity phi translate into the "d" and "f" terms of Darcy-Forchheimer or the C0/C1 parameters of powerLaw ? Does anyone have some references? Cheers, Radu

 July 30, 2007, 05:18 From the porousZone.H: #2 Senior Member   Mark Olesen Join Date: Mar 2009 Location: http://olesenm.github.io/ Posts: 802 Rep Power: 21 From the porousZone.H: Porous zone definition based on cell zones and parameters obtained from a control dictionary constructed from the given stream. The orientation of the porous region is defined with the same notation as a coordinateSystem, but only a Cartesian coordinate system is valid. Implemented porosity models: powerLaw (C0/C1 parameters) S = - rho * C0 * |U|^((C1 - 1) / 2) * U Darcy-Forchheimer (d/f parameters) S = - (mu * U * d + rho/2 * |U| * f) * U The model does not include correction of the temporal terms. This seems to cover all of your questions about orientation, porosity (no temporal terms yets) and the Darcy resistances.

 July 30, 2007, 06:10 Yes, I saw porousZones...so d #3 Member   Radu Mustata Join Date: Mar 2009 Location: Zaragoza, Spain Posts: 97 Rep Power: 10 Yes, I saw porousZones...so d is the inverse of K and f dunno...(?) Does the porosity (phi) of a material enters the fray in anyway? (or just via K, and possibly f)

 July 31, 2007, 01:36 Hi, The porosity is not consi #4 New Member   Masato Otsuki Join Date: Mar 2009 Location: Tokyo, Japan Posts: 26 Rep Power: 10 Hi, The porosity is not considered explicitly for both powerLaw and Darcy-Forchheimer models. i.e. velocity U in these models is not a "physical velocity" but a "superficial velocity". Masato

 November 6, 2009, 07:27 Multiple cell zones #5 Senior Member   Markus Rehm Join Date: Mar 2009 Location: Erlangen (Germany) Posts: 184 Rep Power: 10 Hello, I want to use different cell zones but only the first one is recognized. My porousZones-Dict looks as follows: Code: ```1 ( cat1 { porosity 0.5; Darcy { d d [0 -2 0 0 0 0 0] (11111 11111 11111); f f [0 -1 0 0 0 0 0] (111 111 111); } } ) 2 ( cat2 { porosity 0.6; Darcy { d d [0 -2 0 0 0 0 0] (22222 22222 22222); f f [0 -1 0 0 0 0 0] (222 222 222); } } ) 3 ( cat3 { porosity 0.7; Darcy { d d [0 -2 0 0 0 0 0] (33333 33333 33333); f f [0 -1 0 0 0 0 0] (333 333 333); } } )``` Should it be defined that way? The cell zones are available. Regards, Markus.

 November 6, 2009, 07:47 #6 New Member   Markus Join Date: Sep 2009 Posts: 11 Rep Power: 10 Hi Markus! There may be a problem with your list definitions. Have a look at the UserGuide (Section 4.2.4).

 November 9, 2009, 03:27 #7 Senior Member   Markus Rehm Join Date: Mar 2009 Location: Erlangen (Germany) Posts: 184 Rep Power: 10 Hello, you are right it should read: 3 ( cat1 { porosity 0.5; Darcy { d d [0 -2 0 0 0 0 0] (11111 11111 11111); f f [0 -1 0 0 0 0 0] (111 111 111); } } cat2 { porosity 0.6; Darcy { d d [0 -2 0 0 0 0 0] (22222 22222 22222); f f [0 -1 0 0 0 0 0] (222 222 222); } } cat3 { porosity 0.7; Darcy { d d [0 -2 0 0 0 0 0] (33333 33333 33333); f f [0 -1 0 0 0 0 0] (333 333 333); } } ) Thank you, Markus.

 November 10, 2009, 03:28 #8 Senior Member   Mark Olesen Join Date: Mar 2009 Location: http://olesenm.github.io/ Posts: 802 Rep Power: 21 It might be more convenient, and only very marginally less efficient, if you simply drop the size from the PtrList. For example Code: ```( cat1 { ... } cat2 { ... } cat3 { ... } )``` Internally it will simply use a linked-list during the reading and then move everything over to the PtrList.

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