flopy.seawat.swtvdf module¶

class SeawatVdf(model, mtdnconc=1, mfnadvfd=1, nswtcpl=1, iwtable=1, densemin=0, densemax=0, dnscrit=0.01, denseref=1.0, denseslp=0.025, crhoref=0, firstdt=0.001, indense=1, dense=1.0, nsrhoeos=1, drhodprhd=0.00446, prhdref=0.0, extension='vdf', unitnumber=None, filenames=None, **kwargs)[source]¶

Bases: flopy.pakbase.Package

SEAWAT Variable-Density Flow Package Class.

Parameters:

model (model object) – The model object (of type flopy.seawat.swt.Seawat) to which this package will be added.
(or mt3drhoflg) (mtdnconc) – is the MT3DMS species number that will be used in the equation of state to compute fluid density. This input variable was formerly referred to as MTDNCONC (Langevin and others, 2003). If MT3DRHOFLG = 0, fluid density is specified using items 6 and 7, and flow will be uncoupled with transport if the IMT Process is active. If MT3DRHOFLG > 0, fluid density is calculated using the MT3DMS species number that corresponds with MT3DRHOFLG. A value for MT3DRHOFLG greater than zero indicates that flow will be coupled with transport. If MT3DRHOFLG = -1, fluid density is calculated using one or more MT3DMS species. Items 4a, 4b, and 4c will be read instead of item 4. The dependence of fluid density on pressure head can only be activated when MT3DRHOFLG = -1. A value for MT3DRHOFLG of -1 indicates that flow will be coupled with transport.
mfnadvfd (int) – is a flag that determines the method for calculating the internodal density values used to conserve fluid mass. If MFNADVFD = 2, internodal conductance values used to conserve fluid mass are calculated using a central-in-space algorithm. If MFNADVFD <> 2, internodal conductance values used to conserve fluid mass are calculated using an upstream-weighted algorithm.
nswtcpl (int) – is a flag used to determine the flow and transport coupling procedure. If NSWTCPL = 0 or 1, flow and transport will be explicitly coupled using a one-timestep lag. The explicit coupling option is normally much faster than the iterative option and is recommended for most applications. If NSWTCPL > 1, NSWTCPL is the maximum number of non-linear coupling iterations for the flow and transport solutions. SEAWAT-2000 will stop execution after NSWTCPL iterations if convergence between flow and transport has not occurred. If NSWTCPL = -1, the flow solution will be recalculated only for: The first transport step of the simulation, or The last transport step of the MODFLOW timestep, or The maximum density change at a cell is greater than DNSCRIT.
iwtable (int) – is a flag used to activate the variable-density water-table corrections (Guo and Langevin, 2002, eq. 82). If IWTABLE = 0, the water-table correction will not be applied. If IWTABLE > 0, the water-table correction will be applied.
densemin (float) – is the minimum fluid density. If the resulting density value calculated with the equation of state is less than DENSEMIN, the density value is set to DENSEMIN. If DENSEMIN = 0, the computed fluid density is not limited by DENSEMIN (this is the option to use for most simulations). If DENSEMIN > 0, a computed fluid density less than DENSEMIN is automatically reset to DENSEMIN.
densemax (float) – is the maximum fluid density. If the resulting density value calculated with the equation of state is greater than DENSEMAX, the density value is set to DENSEMAX. If DENSEMAX = 0, the computed fluid density is not limited by DENSEMAX (this is the option to use for most simulations). If DENSEMAX > 0, a computed fluid density larger than DENSEMAX is automatically reset to DENSEMAX.
dnscrit (float) – is a user-specified density value. If NSWTCPL is greater than 1, DNSCRIT is the convergence crite- rion, in units of fluid density, for convergence between flow and transport. If the maximum fluid density difference between two consecutive implicit coupling iterations is not less than DNSCRIT, the program will continue to iterate on the flow and transport equations, or will terminate if NSWTCPL is reached. If NSWTCPL is -1, DNSCRIT is the maximum density threshold, in units of fluid density. If the fluid density change (between the present transport timestep and the last flow solution) at one or more cells is greater than DNSCRIT, then SEAWAT_V4 will update the flow field (by solving the flow equation with the updated density field).
denseref (float) – is the fluid density at the reference concentration, temperature, and pressure. For most simulations, DENSEREF is specified as the density of freshwater at 25 degrees C and at a reference pressure of zero.
drhodc (float) – formerly referred to as DENSESLP (Langevin and others, 2003), is the slope of the linear equation of state that relates fluid density to solute concentration. In SEAWAT_V4, separate values for DRHODC can be entered for as many MT3DMS species as desired. If DRHODC is not specified for a species, then that species does not affect fluid density. Any measurement unit can be used for solute concentration, provided DENSEREF and DRHODC are set properly. DRHODC can be approximated by the user by dividing the density difference over the range of end- member fluids by the difference in concentration between the end-member fluids.
drhodprhd (float) – is the slope of the linear equation of state that relates fluid density to the height of the pressure head (in terms of the reference density). Note that DRHODPRHD can be calculated from the volumetric expansion coefficient for pressure using equation 15. If the simulation is formulated in terms of kilograms and meters, DRHODPRHD has an approximate value of 4.46 x 10-3 kg/m4. A value of zero, which is typically used for most problems, inactivates the dependence of fluid density on pressure.
prhdref (float) – is the reference pressure head. This value should normally be set to zero.
nsrhoeos (int) – is the number of MT3DMS species to be used in the equation of state for fluid density. This value is read only if MT3DRHOFLG = -1.
mtrhospec (int) – is the MT3DMS species number corresponding to the adjacent DRHODC and CRHOREF.
crhoref (float) – is the reference concentration (C0) for species, MTRHOSPEC. For most simulations, CRHOREF should be specified as zero. If MT3DRHOFLG > 0, CRHOREF is assumed to equal zero (as was done in previous versions of SEAWAT).
firstdt (float) – is the length of the first transport timestep used to start the simulation if both of the following two condi- tions are met: 1. The IMT Process is active, and 2. transport timesteps are calculated as a function of the user-specified Courant number (the MT3DMS input variable, PERCEL, is greater than zero).
indense (int) – is a flag. INDENSE is read only if MT3DRHOFLG is equal to zero. If INDENSE < 0, values for the DENSE array will be reused from the previous stress period. If it is the first stress period, values for the DENSE array will be set to DENSEREF. If INDENSE = 0, values for the DENSE array will be set to DENSEREF. If INDENSE >= 1, values for the DENSE array will be read from item 7. If INDENSE = 2, values read for the DENSE array are assumed to represent solute concentration, and will be converted to density values using the equation of state.
dense (Transient3d) – A float or array of floats (nlay, nrow, ncol) should be assigned as values to a dictionary related to keys of period number. dense is the fluid density array read for each layer using the MODFLOW-2000 U2DREL array reader. The DENSE array is read only if MT3DRHOFLG is equal to zero. The DENSE array may also be entered in terms of solute concentration, or any other units, if INDENSE is set to 2 and the constants used in the density equation of state are specified appropriately.
extension (string) – Filename extension (default is ‘vdf’)
unitnumber (int) – File unit number (default is 37).

Notes

In swt_4 mtdnconc became mt3drhoflg. If the latter one is defined in kwargs, it will overwrite mtdnconc. Same goes for denseslp, which has become drhodc.

When loading an existing SEAWAT model that has DENSE specified as concentrations, the load process will convert those concentrations into density values using the equation of state. This is only relevant when mtdnconc (or mt3drhoflg) is set to zero.

Examples

>>> import flopy
>>> m = flopy.seawat.Seawat()
>>> lpf = flopy.seawat.SeawatVdf(m)

classmethod load(f, model, nper=None, ext_unit_dict=None)[source]¶

Load an existing package.

Parameters:	f (filename or file handle) – File to load. model (model object) – The model object (of type `flopy.seawat.swt.Seawat`) to which this package will be added. nper (int) – The number of stress periods. If nper is None, then nper will be obtained from the model object. (default is None). ext_unit_dict (dictionary, optional) – If the arrays in the file are specified using EXTERNAL, or older style array control records, then f should be a file handle. In this case ext_unit_dict is required, which can be constructed using the function `flopy.utils.mfreadnam.parsenamefile`.
Returns:	vdf – SeawatVdf object.
Return type:	SeawatVdf object

Examples

>>> import flopy
>>> mf = flopy.modflow.Modflow()
>>> dis = flopy.modflow.ModflowDis(mf)
>>> mt = flopy.mt3d.Mt3dms()
>>> swt = flopy.seawat.Seawat(modflowmodel=mf, mt3dmsmodel=mt)
>>> vdf = flopy.seawat.SeawatVdf.load('test.vdf', m)

unitnumber = 37¶

write_file()[source]¶

Write the package file

Returns:
Return type:	None