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#1 |
New Member
mrzarei
Join Date: Jan 2021
Posts: 5
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Hi
I want to use porous media (darcy law) in reef3d, like kamath 2015 paper with application in OWC wave energy converter. But unfortunately I do not know how and where I should apply it. I would be so thankful if anyone can help me. |
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#2 |
Super Moderator
Hans Bihs
Join Date: Jun 2009
Location: Trondheim, Norway
Posts: 211
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Porous media can be invoked by using B 240. In general though, the VRANS option is the more consistent way to calculate flow through porous media. VRANS can be used with options B 260 to B 310. See here for more details: https://reef3d.files.wordpress.com/2...cej_porous.pdf
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#3 | |
New Member
mrzarei
Join Date: Jan 2021
Posts: 5
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Quote:
I want to validate kamath paper in 2015 about oscillating water column, But unfortunately I have some problems. In definition of porous media, I defined it at the orifice along with the parameters in the following command. but I have a problem with velocity, velocities exceeding the critical value. I would be so thankful if you could help me with the definition of porous media location. B 240 * double Darcy porous media as rectangular box: C;D;xstar t;xend;ystar t;yend;zstar t;zend |
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#4 |
New Member
mrzarei
Join Date: Jan 2021
Posts: 5
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I want to use Reef3D, Please only refer me to the equation that used for "D" in darcy porous media, B 240.
Unfotunately I can't find it's equation in Reef3D codes. |
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#5 |
Super Moderator
Hans Bihs
Join Date: Jun 2009
Location: Trondheim, Norway
Posts: 211
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For the OWC, you only use "C" from B240, "D" is zero. The background can be found here: https://reef3d.files.wordpress.com/2..._ijme-2015.pdf - have a look at equations 14 and 15. The other parameters describe the volume where the porous media is active.
In addition to B 240, also use B 241 1. This way, the porous media only impacts the vertical velocity component. |
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#6 |
Super Moderator
Hans Bihs
Join Date: Jun 2009
Location: Trondheim, Norway
Posts: 211
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The implementation can be found in iowave_velsource.cpp.
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#7 |
New Member
mrzarei
Join Date: Jan 2021
Posts: 5
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Thanks a lot
I read both of kamath papers about OWC. He used C as a linear parameter of darcy law, but I want to use D as a nonlinear parameter for validation of an experiment that I read in another paper. However, if you remember the formula that includes D parameter, please send it to me. Regards |
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#8 |
Super Moderator
Hans Bihs
Join Date: Jun 2009
Location: Trondheim, Norway
Posts: 211
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The complete formula is implemented for B 240, including the non-linear part:
Code:
porousterm = p->B240_D[n]*a->visc(i,j,k)*a->u(i,j,k) + 0.5*p->B240_C[n]*a->u(i,j,k)*fabs(a->u(i,j,k)); |
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#9 |
New Member
Bhargav
Join Date: Aug 2022
Posts: 5
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Hi,
I am trying to run a CFD case (OWC with porous media as a turbine) to familiarize myself with the simulations. But unfortunately, there seems to be some error. Can anyone have a look? A file containing the code and STL file is attached. Is it because of my STL file? When I applied porous media on the solid surface of the OWC, the simulation ran well without any errors, but I was not getting airflow through the orifice when I visualized the VTU file in paravew, and the results are also not matching with the published literature. (Do I need to provide porous media on a solid surface or on an orifice?) I also ran a code by providing a porous media on the orifice, but simulations popped up an error during the reef3d run saying EMERGENCY STOP -- velocities exceeding critical value N 61. Any help on this matter is appreciated. Thanks |
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#10 | |
New Member
mrzarei
Join Date: Jan 2021
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Hi
In reef3D, two parameters of C & D were defined oppositely. you should write C instead of D and D instead of C. I checked it and got good results. Quote:
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#11 |
New Member
Bhargav
Join Date: Aug 2022
Posts: 5
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I'm having trouble figuring out the permeability coefficient mentioned in the publication by Arun Kamath et al (2015). As you can see from the attached image, they have provided the P and q values, and we are aware of the water's viscosity, but what about the A and L values? How did they arrive at 1/Kp=500000000?
Kamath.JPG Reference: Kamath, Arun, Bihs, Hans and Arntsen, Řivind A. “Numerical investigations of the hydrodynamics of an oscillating water column device.” Ocean Engineering Vol. 102 (2015): pp. 40–50. |
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Tags |
darcy's law, porous media, reef3d |
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