Evaluating the pressure drop across complex Porous Media

gsabhishek · June 12, 2018, 19:23

Hi All,

I have a complex rigid solid structure in a channel with low Re(<10) incompressible flow. I intend to find out the the pressure drop across the solid. The domain is shown below :

here

This being a low Re flow we can apply a darcy type flow relation to evaluate the pressure drop. But unfortunately, the solid body is complex and evolving... so estimating its porosity/permeability is quite difficult.

I intend to use the N-S equation as follows :
$\frac{\partial V}{\partial t} + (V.\nabla)V = -\frac{\nabla p}{\rho} + \eta\nabla^2V + g + \alpha10^6 V$
here the last term makes the flow zero on the surface and inside the solid. The domain is initialized such that $\alpha$ =0 for liquid and $\alpha$ =1 for solid.

Solid Structure and fluid flow are not coupled. The sequence is as follows
1) The solid structure evolves (very slow)
2) I solve the navier stokes everywhere in the domain untill steady state
3) Next evolution step for solid and repeat with step 2

Could you please help me with understanding the following :
> Is the current form of the equation capturing the physics of the problem. If not how should I approach it
> I might have capillary effects in some regions. How do I handle them
> I intend to use OpenFoam for solving this. What would be a good validation case

thanks for your time.

Utkan · November 27, 2020, 19:51

How did you solve your problem?

aerosayan · November 28, 2020, 05:33

Quote:

Originally Posted by gsabhishek

The domain is shown below :

here

I don't know the solution to your problem. I wanted to let you know that your link is broken and the dropbox file seems to be deleted.

June 12, 2018, 19:23	Evaluating the pressure drop across complex Porous Media	#1
gsabhishek New Member Join Date: Feb 2017 Posts: 5 Rep Power: 9	Hi All, I have a complex rigid solid structure in a channel with low Re(<10) incompressible flow. I intend to find out the the pressure drop across the solid. The domain is shown below : here This being a low Re flow we can apply a darcy type flow relation to evaluate the pressure drop. But unfortunately, the solid body is complex and evolving... so estimating its porosity/permeability is quite difficult. I intend to use the N-S equation as follows : $\frac{\partial V}{\partial t} + (V.\nabla)V = -\frac{\nabla p}{\rho} + \eta\nabla^2V + g + \alpha10^6 V$ here the last term makes the flow zero on the surface and inside the solid. The domain is initialized such that $\alpha$ =0 for liquid and $\alpha$ =1 for solid. Solid Structure and fluid flow are not coupled. The sequence is as follows 1) The solid structure evolves (very slow) 2) I solve the navier stokes everywhere in the domain untill steady state 3) Next evolution step for solid and repeat with step 2 Could you please help me with understanding the following : > Is the current form of the equation capturing the physics of the problem. If not how should I approach it > I might have capillary effects in some regions. How do I handle them > I intend to use OpenFoam for solving this. What would be a good validation case thanks for your time.

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November 27, 2020, 19:51		#2
Utkan New Member Utkan Erdem Join Date: Sep 2020 Posts: 19 Rep Power: 6	How did you solve your problem?