
[Sponsors] 
How to define the porous inertial resistance and viscous resistance of porous media? 

LinkBack  Thread Tools  Display Modes 
June 27, 2012, 00:54 
How to define the porous inertial resistance and viscous resistance of porous media?

#1 
New Member
Aaron Gao
Join Date: Jun 2012
Posts: 3
Rep Power: 7 
hello everyone
I have two questions about porous media. can you help me? thanks a lot.
1. How to define the porous inertial resistance and viscous resistance of porous media? what value can I use to input in ccm+? for example. I know air flux ,pressure drop and the shape of the porous media. (1). A cuboid, the thickness is c, and the Flow direction is thickness direction ,then i can use excel to analog polynomial curve: y=aX˛+bX.(y=static pressure drop,X= flow velocity) (2). A cylinder, the thickness is c, and the flow direction is along radial direction form out to the inner. Of course i can use excel to analog polynomial curve: y=aX˛+bX. but what can i do the next? 2. You know when I calculate the flow velocity, I need to use the air flux to divide by section area. It is very easy to gain the section area in cuboid model, but what about the cylinder?? Last edited by pinfan143; June 27, 2012 at 01:22. 

June 28, 2012, 03:33 

#2 
Senior Member
siamak rahimi ardkapan
Join Date: Jul 2010
Location: Copenhagen, Denmark
Posts: 218
Rep Power: 11 
Usually the resistances are in the order of thousands, except for the direction that the fluid can move easier ( for example in the case of filter, the resistance will be in the order of 10). good luck


July 6, 2012, 18:24 

#3 
Senior Member
Join Date: Oct 2009
Location: Germany
Posts: 637
Rep Power: 14 
For the cylinder, I would use the average velocity as long as there is no huge difference between min and max velocity. So when you divide the volume flow rate by some cross sectional area, use the mantle area of a cylinder with the mean radius.
Calculate a and b and put it in the region values. For the radial direction of a cylinder, you might create a cylindrical coordinate system first. When you don't want to allow a flow in axial or tangential direction, put a maximum of 1000 times the resistance in radial direction. Otherwise it might get unstable.
__________________
We do three types of jobs here: GOOD, FAST AND CHEAP You may choose any two! 

July 10, 2012, 00:15 

#4  
New Member
Aaron Gao
Join Date: Jun 2012
Posts: 3
Rep Power: 7 
Quote:


July 19, 2015, 16:06 

#5 
New Member
Join Date: Dec 2014
Posts: 3
Rep Power: 4 
Hi
I'm trying to model vegetation as 3D porous media. As I am an architecture, have some queries, hope someone can help me out. Is there any relationship between pressure drop and pressure loss coefficient? I do not know how to set these two parameters in fluent: Viscous resistance coefficients and Inertial resistance. How can I get these? Thanks. 

July 21, 2015, 11:52 

#6 
Senior Member
Matt
Join Date: Aug 2014
Posts: 611
Rep Power: 9 
sahra, I have a spreadsheet I can share. send me a private message with your email address.


Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
viscous resistance coefficients in Porous media  choyong  FLUENT  9  December 15, 2014 21:01 
UDF for viscous resistance for porous media with time variable  benson621  Fluent UDF and Scheme Programming  2  November 24, 2011 12:59 
Viscous and Inertial Resistance in Porous Media  aulu  FLUENT  0  September 14, 2011 05:21 
Multiphase Porous Media Flow  Convergence Issues  VT_Bromley  FLUENT  5  March 23, 2011 11:38 
how to calculate the viscous and inertial resistance coefficients?  omurakbayir  FLUENT  1  November 22, 2010 23:36 