- drainage(im, voxel_size, pc=None, inlets=None, outlets=None, residual=None, bins=25, delta_rho=1000, g=9.81, sigma=0.072, theta=180)#
Simulate drainage using image-based sphere insertion, optionally including gravity
im (ndarray) – The image of the porous media with
Truevalues indicating the void space.
voxel_size (float) – The resolution of the image in meters per voxel edge.
pc (ndarray, optional) – An array containing precomputed capillary pressure values in each voxel. If not provided then the Washburn equation is used with the provided values of
theta. If the image is 2D only 1 principle radii of curvature is included.
inlets (ndarray (default = x0)) – A boolean image the same shape as
Truevalues indicating the inlet locations. See Notes. If not specified it is assumed that the invading phase enters from the bottom (x=0).
outlets (ndarray, optional) – Similar to
inletsexcept defining the outlets. This image is used to assess trapping. If not provided then trapping is ignored, otherwise a mask indicating which voxels were trapped is included amoung the returned data.
residual (ndarray, optional) – A boolean array indicating the locations of any residual defending phase. This is added to the intermediate image prior to trimming disconnected clusters, so will create connections to some clusters that would otherwise be removed. The residual phase is indicated in the final image by
-np.infvalues, since there are invaded at all applied capillary pressures.
bins (int or array_like (default = 25)) – The range of pressures to apply. If an integer is given then bins will be created between the lowest and highest pressures in the
pc. If a list is given, each value in the list is used directly in order.
delta_rho (float (default = 997)) – The density difference between the invading and defending phases. Note that if air is displacing water this value should be -997 (1-998).
g (float (default = 9.81)) – The gravitational constant prevailing for the simulation. The default is 9.81. If the domain is on an angle, such as a tilted micromodel, this value should be scaled appropriately by the user (i.e. g = 9.81 sin(alpha) where alpha is the angle relative to the horizonal). Setting this value to zeor removes any gravity effects.
sigma (float (default = 0.072)) – The surface tension of the fluid pair. If
pcis provided this is ignored.
theta (float (defaut = 180)) – The contact angle of the sytem in degrees. If
pcis provded this is ignored.
results – A dataclass-like object with the following attributes:
A numpy array with each voxel value indicating the capillary pressure at which it was invaded
A numpy array with each voxel value indicating the global saturation value at the point it was invaded
1D array of capillary pressure values that were applied
1D array of non-wetting phase saturations for each applied value of capillary pressure (
- Return type
The direction of gravity is always towards the x=0 axis
This algorithm has only been tested for gravity stabilized configurations, meaning the more dense fluid is on the bottom. Be sure that
inletsare specified accordingly.
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