# Source code for imod.wq.adv

```
import textwrap
from imod.wq.pkgbase import Package
[docs]class AdvectionFiniteDifference(Package):
"""
Solve the advection term using the explicit Finite Difference method
(MIXELM = 0) with upstream weighting
Attributes
----------
courant: float
Courant number (PERCEL) is the number of cells (or a fraction of a cell)
advection will be allowed in any direction in one transport step. For
implicit finite-difference or particle tracking based schemes, there is
no limit on PERCEL, but for accuracy reasons, it is generally not set
much greater than one. Note, however, that the PERCEL limit is checked
over the entire model grid. Thus, even if PERCEL > 1, advection may not
be more than one cell’s length at most model locations. For the explicit
finite-difference, PERCEL is also a stability constraint, which must not
exceed one and will be automatically reset to one if a value greater
than one is specified.
weighting : string {"upstream", "central"}, optional
Indication of which weighting scheme should be used, set to default
value "upstream" (NADVFD = 0 or 1)
Default value: "upstream"
"""
_pkg_id = "adv"
_keywords = {"weighting": {"upstream": 0, "central": 1}}
_template = (
"[adv]\n"
" mixelm = 0\n"
" percel = {courant}\n"
" nadvfd = {weighting}\n"
)
[docs] def __init__(self, courant=0.75, weighting="upstream"):
super().__init__()
self["courant"] = courant
self["weighting"] = weighting
def _pkgcheck(self, ibound=None):
self._check_positive(["courant"])
[docs]class AdvectionMOC(Package):
"""
Solve the advection term using the Method of Characteristics (MIXELM = 1)
Nota bene: number of particles settings have not been tested. The defaults
here are chosen conservatively, with many particles. This increases both
memory usage and computational effort.
Attributes
-----------
courant: float
Courant number (PERCEL) is the number of cells (or a fraction of a cell)
advection will be allowed in any direction in one transport step. For
implicit finite-difference or particle tracking based schemes, there is
no limit on PERCEL, but for accuracy reasons, it is generally not set
much greater than one. Note, however, that the PERCEL limit is checked
over the entire model grid. Thus, even if PERCEL > 1, advection may not
be more than one cell’s length at most model locations. For the explicit
finite-difference, PERCEL is also a stability constraint, which must not
exceed one and will be automatically reset to one if a value greater
than one is specified.
max_nparticles: int
is the maximum total number of moving particles allowed (MXPART).
tracking: string {"euler", "runge-kutta", "hybrid"}, optional
indicates which particle tracking algorithm is selected for the
Eulerian-Lagrangian methods. ITRACK = 1, the first-order Euler algorithm is
used; ITRACK = 2, the fourth-order Runge-Kutta algorithm is used; this
option is computationally demanding and may be needed only when PERCEL is
set greater than one. ITRACK = 3, the hybrid 1st and 4th order algorithm is
used; the Runge- Kutta algorithm is used in sink/source cells and the cells
next to sinks/sources while the Euler algorithm is used elsewhere.
Default value is "hybrid".
weighting_factor: float, optional
is a concentration weighting factor (WD) between 0.5 and 1. It is used for
operator splitting in the particle tracking based methods. The value of
0.5 is generally adequate. The value may be adjusted to achieve better
mass balance. Generally, it can be increased toward 1.0 as advection
becomes more dominant.
Default value: 0.5.
dconcentration_epsilon: float, optional
is a small Relative Cell Concentration Gradient below which advective
transport is considered negligible. A value around 10-5 is generally
adequate.
Default value: 1.0e-5.
nplane: int, optional
is a flag indicating whether the random or fixed pattern is selected for
initial placement of moving particles. NPLANE = 0, the random pattern is
selected for initial placement. Particles are distributed randomly in
both the horizontal and vertical directions by calling a random number
generator. This option is usually preferred and leads to smaller mass
balance discrepancy in nonuniform or diverging/converging flow fields.
NPLANE > 0, the fixed pattern is selected for initial placement. The
value of NPLANE serves as the number of vertical "planes" on which
initial particles are placed within each cell block. The fixed pattern
may work better than the random pattern only in relatively uniform flow
fields. For two-dimensional simulations in plan view, set NPLANE = 1.
For cross sectional or three-dimensional simulations, NPLANE = 2 is
normally adequate. Increase NPLANE if more resolution in the vertical
direction is desired.
Default value: 2.
nparticles_no_advection: int, optional
is number of initial particles per cell to be placed at cells where the
Relative Cell Concentration Gradient is less than or equal to DCEPS.
Generally, NPL can be set to zero since advection is considered
insignificant when the Relative Cell Concentration Gradient is less than
or equal to DCEPS. Setting NPL equal to NPH causes a uniform number of
particles to be placed in every cell over the entire grid (i.e., the
uniform approach).
Default value: 10.
nparticles_advection: int, optional
is number of initial particles per cell to be placed at cells where the
Relative Cell Concentration Gradient is greater than DCEPS. The
selection of NPH depends on the nature of the flow field and also the
computer memory limitation. Generally, use a smaller number in
relatively uniform flow fields and a larger number in relatively
nonuniform flow fields. However, values exceeding 16 in twodimensional
simulation or 32 in three-dimensional simulation are rarely necessary.
If the random pattern is chosen, NPH particles are randomly distributed
within the cell block. If the fixed pattern is chosen, NPH is divided by
NPLANE to yield the number of particles to be placed per vertical plane.
Default value: 40.
cell_min_nparticles: int, optional
is the minimum number of particles allowed per cell. If the number of
particles in a cell at the end of a transport step is fewer than NPMIN,
new particles are inserted into that cell to maintain a sufficient
number of particles. NPMIN can be set to zero in relatively uniform flow
fields, and a number greater than zero in diverging/converging flow
fields. Generally, a value between zero and four is adequate.
Default value is 5.
cell_max_nparticles: int, optional
is the maximum number of particles allowed per cell. If the number of
particles in a cell exceeds NPMAX, all particles are removed from that
cell and replaced by a new set of particles equal to NPH to maintain
mass balance. Generally, NPMAX can be set to approximately twice of NPH.
Default value: 80.
"""
_pkg_id = "adv"
_keywords = {"tracking": {"euler": 1, "runge-kutta": 2, "hybrid": 3}}
_template = textwrap.dedent(
"""
[adv]
mixelm = 1
percel = {courant}
mxpart = {max_nparticles}
itrack = {tracking}
wd = {weighting_factor}
dceps = {dconcentration_epsilon}
nplane = {nplane}
npl = {nparticles_no_advection}
nph = {nparticles_advection}
npmin = {cell_min_nparticles}
npmax = {cell_max_nparticles}
"""
)
[docs] def __init__(
self,
courant=0.75,
tracking="hybrid",
weighting_factor=0.5,
dconcentration_epsilon=1.0e-5,
nplane=2,
nparticles_no_advection=10,
nparticles_advection=40,
cell_min_nparticles=5,
cell_max_nparticles=80,
):
super().__init__()
self["courant"] = courant
self["tracking"] = tracking
self["weighting_factor"] = weighting_factor
self["dconcentration_epsilon"] = dconcentration_epsilon
self["nplane"] = nplane
self["nparticles_no_advection"] = nparticles_no_advection
self["nparticles_advection"] = nparticles_advection
self["cell_min_nparticles"] = cell_min_nparticles
self["cell_max_nparticles"] = cell_max_nparticles
def _pkgcheck(self, ibound=None):
self._check_positive(["courant", "weighting_factor"])
[docs]class AdvectionModifiedMOC(Package):
"""
Solve the advention term using the Modified Method of Characteristics (MIXELM = 2)
Courant number (PERCEL) is the number of cells (or a fraction of a
cell) advection will be allowed in any direction in one transport step.
Attributes
----------
courant: float
Courant number (PERCEL) is the number of cells (or a fraction of a cell)
advection will be allowed in any direction in one transport step. For
implicit finite-difference or particle tracking based schemes, there is
no limit on PERCEL, but for accuracy reasons, it is generally not set
much greater than one. Note, however, that the PERCEL limit is checked
over the entire model grid. Thus, even if PERCEL > 1, advection may not
be more than one cell’s length at most model locations. For the explicit
finite-difference, PERCEL is also a stability constraint, which must not
exceed one and will be automatically reset to one if a value greater
than one is specified.
tracking: string, {"euler", "runge-kutta", "hybrid"}
indicates which particle tracking algorithm is selected for the
Eulerian-Lagrangian methods. ITRACK = 1, the first-order Euler algorithm is
used; ITRACK = 2, the fourth-order Runge-Kutta algorithm is used; this
option is computationally demanding and may be needed only when PERCEL is
set greater than one. ITRACK = 3, the hybrid 1st and 4th order algorithm is
used; the Runge- Kutta algorithm is used in sink/source cells and the cells
next to sinks/sources while the Euler algorithm is used elsewhere.
weighting_factor: float
is a concentration weighting factor (WD) between 0.5 and 1. It is used for
operator splitting in the particle tracking based methods. The value of
0.5 is generally adequate. The value may be adjusted to achieve better
mass balance. Generally, it can be increased toward 1.0 as advection
becomes more dominant.
dconcentration_epsilon: float, optional
is a small Relative Cell Concentration Gradient (DCEPS) below which advective
transport is considered negligible. A value around 1.0e-5 is generally
adequate.
Default value: 1.0e-5.
sink_particle_placement: int
indicates whether the random or fixed pattern is selected for initial
placement of particles to approximate sink cells in the MMOC scheme.
(NLSINK)
sink_nparticles: int
is the number of particles used to approximate sink cells in the MMOC
scheme. (NPSINK)
"""
_pkg_id = "adv"
_keywords = {"tracking": {"euler": 1, "runge-kutta": 2, "hybrid": 3}}
_template = (
"[adv]\n"
" mixelm = 2\n"
" percel = {courant}\n"
" itrack = {tracking}\n"
" wd = {weighting_factor}\n"
" interp = 1\n"
" nlsink = {sink_particle_placement}\n"
" npsink = {sink_nparticles}\n"
)
[docs] def __init__(
self,
courant=1.0,
tracking="hybrid",
weighting_factor=0.5,
dconcentration_epsilon=1.0e-5,
sink_particle_placement=2,
sink_nparticles=40,
):
super().__init__()
self["courant"] = courant
self["tracking"] = tracking
self["weighting_factor"] = weighting_factor
self["sink_particle_placement"] = sink_particle_placement
self["sink_nparticles"] = sink_nparticles
def _pkgcheck(self, ibound=None):
self._check_positive(["courant", "weighting_factor"])
[docs]class AdvectionHybridMOC(Package):
"""
Hybrid Method of Characteristics and Modified Method of Characteristics with
MOC or MMOC automatically and dynamically selected (MIXELM = 3)
Attributes
----------
courant: float
Courant number (PERCEL) is the number of cells (or a fraction of a cell)
advection will be allowed in any direction in one transport step. For
implicit finite-difference or particle tracking based schemes, there is
no limit on PERCEL, but for accuracy reasons, it is generally not set
much greater than one. Note, however, that the PERCEL limit is checked
over the entire model grid. Thus, even if PERCEL > 1, advection may not
be more than one cell’s length at most model locations. For the explicit
finite-difference, PERCEL is also a stability constraint, which must not
exceed one and will be automatically reset to one if a value greater
than one is specified.
max_particles: int
is the maximum total number of moving particles allowed (MXPART).
tracking: int
indicates which particle tracking algorithm is selected for the
Eulerian-Lagrangian methods. ITRACK = 1, the first-order Euler algorithm is
used; ITRACK = 2, the fourth-order Runge-Kutta algorithm is used; this
option is computationally demanding and may be needed only when PERCEL is
set greater than one. ITRACK = 3, the hybrid 1st and 4th order algorithm is
used; the Runge- Kutta algorithm is used in sink/source cells and the cells
next to sinks/sources while the Euler algorithm is used elsewhere.
weighting_factor: float
is a concentration weighting factor (WD) between 0.5 and 1. It is used for
operator splitting in the particle tracking based methods. The value of
0.5 is generally adequate. The value may be adjusted to achieve better
mass balance. Generally, it can be increased toward 1.0 as advection
becomes more dominant.
dceps: float
is a small Relative Cell Concentration Gradient below which advective
transport is considered negligible. A value around 10-5 is generally
adequate.
nplane: int
is a flag indicating whether the random or fixed pattern is selected for
initial placement of moving particles. NPLANE = 0, the random pattern is
selected for initial placement. Particles are distributed randomly in
both the horizontal and vertical directions by calling a random number
generator. This option is usually preferred and leads to smaller mass
balance discrepancy in nonuniform or diverging/converging flow fields.
NPLANE > 0, the fixed pattern is selected for initial placement. The
value of NPLANE serves as the number of vertical "planes" on which
initial particles are placed within each cell block. The fixed pattern
may work better than the random pattern only in relatively uniform flow
fields. For two-dimensional simulations in plan view, set NPLANE = 1.
For cross sectional or three-dimensional simulations, NPLANE = 2 is
normally adequate. Increase NPLANE if more resolution in the vertical
direction is desired.
npl: int
is number of initial particles per cell to be placed at cells where the
Relative Cell Concentration Gradient is less than or equal to DCEPS.
Generally, NPL can be set to zero since advection is considered
insignificant when the Relative Cell Concentration Gradient is less than
or equal to DCEPS. Setting NPL equal to NPH causes a uniform number of
particles to be placed in every cell over the entire grid (i.e., the
uniform approach).
nph: int
is number of initial particles per cell to be placed at cells where the
Relative Cell Concentration Gradient is greater than DCEPS. The
selection of NPH depends on the nature of the flow field and also the
computer memory limitation. Generally, use a smaller number in
relatively uniform flow fields and a larger number in relatively
nonuniform flow fields. However, values exceeding 16 in twodimensional
simulation or 32 in three-dimensional simulation are rarely necessary.
If the random pattern is chosen, NPH particles are randomly distributed
within the cell block. If the fixed pattern is chosen, NPH is divided by
NPLANE to yield the number of particles to be placed per vertical plane.
npmin: int
is the minimum number of particles allowed per cell. If the number of
particles in a cell at the end of a transport step is fewer than NPMIN,
new particles are inserted into that cell to maintain a sufficient
number of particles. NPMIN can be set to zero in relatively uniform flow
fields, and a number greater than zero in diverging/converging flow
fields. Generally, a value between zero and four is adequate.
npmax: int
is the maximum number of particles allowed per cell. If the number of
particles in a cell exceeds NPMAX, all particles are removed from that
cell and replaced by a new set of particles equal to NPH to maintain
mass balance. Generally, NPMAX can be set to approximately twice of NPH.
dchmoc: real
is the critical Relative Concentration Gradient for controlling the
selective use of either MOC or MMOC in the HMOC solution scheme. The MOC
solution is selected at cells where the Relative Concentration Gradient
is greater than DCHMOC; The MMOC solution is selected at cells where the
Relative Concentration Gradient is less than or equal to DCHMOC
"""
_pkg_id = "adv"
[docs] def __init__(
self,
courant=0.75,
tracking="hybrid",
weighting_factor=0.5,
dconcentration_epsilon=1.0e-5,
nplane=2,
nparticles_no_advection=10,
nparticles_advection=40,
cell_min_nparticles=5,
cell_max_nparticles=80,
sink_particle_placement=2,
sink_nparticles=40,
dconcentration_hybrid=1.0e-4,
):
super().__init__()
self["courant"] = courant
self["tracking"] = tracking
self["weighting_factor"] = weighting_factor
self["dconcentration_epsilon"] = dconcentration_epsilon
self["nplane"] = nplane
self["nparticles_no_advection"] = nparticles_no_advection
self["nparticles_advection"] = nparticles_advection
self["cell_min_nparticles"] = cell_min_nparticles
self["cell_max_nparticles"] = cell_max_nparticles
self["sink_particle_placement"] = sink_particle_placement
self["sink_nparticles"] = sink_nparticles
self["dconcentration_hybrid"] = dconcentration_hybrid
def _pkgcheck(self, ibound=None):
self._check_positive(["courant", "weighting_factor"])
[docs]class AdvectionTVD(Package):
"""
Total Variation Diminishing (TVD) formulation (ULTIMATE, MIXELM = -1).
Attributes
----------
courant : float
Courant number (PERCEL) is the number of cells (or a fraction of a cell)
advection will be allowed in any direction in one transport step. For
implicit finite-difference or particle tracking based schemes, there is
no limit on PERCEL, but for accuracy reasons, it is generally not set
much greater than one. Note, however, that the PERCEL limit is checked
over the entire model grid. Thus, even if PERCEL > 1, advection may not
be more than one cell’s length at most model locations. For the explicit
finite-difference, PERCEL is also a stability constraint, which must not
exceed one and will be automatically reset to one if a value greater
than one is specified.
"""
_pkg_id = "adv"
_template = "[adv]\n" " mixelm = -1\n" " percel = {courant}\n"
def _pkgcheck(self, ibound=None):
self._check_positive(["courant"])
```