porespy.filters.capillary_transform#

porespy.filters.capillary_transform(im: numpy.typing.NDArray, dt: numpy.typing.NDArray = None, sigma: float = 1.0, theta: float = 180, g: float = 0.0, rho_wp: float = 0.0, rho_nwp: float = 0.0, voxel_size: float = 1.0, spacing: float = None)#

Uses the Washburn equation to convert distance transform values to a capillary transform.

Parameters:

  • im (ndarray) – A boolean image describing the porous medium with True values indicating the phase of interest.

  • dt (ndarray, optional) – The distance transform of the void phase. If not provided it will be calculated, so some time can be save if a pre-computed array is already available.

  • sigma (scalar (default = 1.0)) – The surface tension of the fluid-fluid interface.

  • theta (scalar (default = 180)) – The contact angle of the fluid-fluid-solid system, in degrees, measured through the non-wetting phase. It must be >90.

  • g (scalar (default = 0)) – The gravitational constant acting on the fluids. Gravity is assumed to act toward the x=0 axis. To have gravity act in different directions use np.swapaxes(im, 0, ax) where ax is the desired direction.

  • rho_nwp (scalar) – The density of the non-wetting fluid

  • rho_wp (scalar) – The density of the wetting fluid

  • voxel_size (scalar (default = 0.0)) – The resolution of the image

  • spacing (scalar (default = None)) – If a 2D image is provided, this value is used to compute the second radii of curvature. Setting it to np.inf will make the calculation truly 2D since only one radii of curvature is considered. Setting it to None will force the calculation to be 3D. If im is 3D this argument is ignored. This should be in units of physical length, not voxels.

Notes

All physical properties should be in self-consistent units, and it is strongly recommended to use SI for everything.

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