Constitutive law of flow in porous media for a pipe element
This law is only used for non linear analysis of seepage in porous media.
The case of free surface seepage is also treated.
This law is used for one‑dimensional flow.
Prepro: LECOUP.F
Lagamine: ECOU1.F
| Plane stress state | YES |
| Plane strain state | YES |
| Axisymmetric state | YES |
| 3D state | YES |
| Generalized plane state | YES |
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 116 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing |
None
The permeability $k$ is an intrinsic permeability $\left(\left[L^2\right]\right)$ \[k_{intrinsic}=K\frac{\mu_f}{\rho_fg} \\ [L^2]=[LT^{-1}]\frac{[ML^{-1}T^{-1}]}{[ML^{-3}][LT^{-2}]} \]
Where $K$ is the permeability coefficient $(\left[LT^{-1}\right])$
| Line 1 (7G10.0) | |
|---|---|
| PERMEA | soil intrinsic permeability (=$k$) |
| RHO | specific mass of the fluid (=$\rho_f$) |
| POROS | soil porosity (=$n_0$) |
| EMMAG | storage coefficient (=$C_p$) |
| ALPHA | $\alpha$ & $\beta$: parameter used to define the curve $\theta = \theta(p)$ |
| BETA | |
| AREA | cross section of the pipe |
| Line 2 (1G10.0) | |
| VISCO | fluid dynamic viscosity ($\mu_f=10^{-3}$=default value for water at 20°C) |
The evolution of the stored fluid volume ($\theta$) with the fluid pressure ($p$) is given by the following functions:
3
| SIG(1) | fluid flow in the pipe |
| SIG(2) | fluid flow stored as a consequence of the evolution of soil porosity |
| SIG(3) | 0 (meaningless) |
1
| Q(1) | cross section of the pipe |