Known fields¶
Known fields can be used to specify boundary and initial conditions. If they are the same then one field can be used for both avoiding repeated definitions. Known fields can also be used to specify custom fields that cannot easily be described in C++, like the regular wave fields that are implemented. Known fields can also be used to specify damping zones in a domain.

name
Name of the field. Used to refer to the field from other places

type
The field type, one of
AiryWaves
BlendedField
FreeSurfaceZone
MaxField
MinField
RaschiiWaves
ScalarField
VectorField
WaterBlock
WaveOutflow

stationary
Set this to true/on (default is off) if you want to stop the field recomputing its value every time

plot
Most fields support plotting their value to a file which can be enabled by this setting
AiryWaves¶
Standard linear waves. This field exposes the following functions:
field_name/
elevation
field_name/
c
field_name/
rho
field_name/
uhoriz
field_name/
uvert
field_name/
u
 vector field, either [uhoriz, uvert] or [uhoriz, 0, uvert]field_name/
pdyn
field_name/
pstat
field_name/
ptot

depth
The water depth

depth_above
Height of the air phase above the still water

still_water_position
The location of the the still water plane. It will be equal to the depth if the origin is at the bottom.

omegas, periods, wave_lengths, wave_numbers
List of numbers. You must specify one and only one of these

wave_phases
The phase of the waves, list of numbers, default is 0 for all waves

amplitudes
The wave amplitudes. List of numbers, no default values

current_speed, wind_speed
A superinposed current in the water phase / air phase respectively

ramp_time
Ramp up the amplitudes over a given time interval, default 0.

ramp_time
Ramp up the amplitudes over a given time interval, default 0.

colour_projection_degree
Project the colour function to DG0 using quadrature of this degree, default 6 (set degree to 1 to prevent this projection and just use interpolation instead)
RaschiiWaves¶
Construct regular waves by use of the Rascii Python library to construct C++ code that describes the wave field

wave_model
The Raschii wave model to use, default is
Fenton
. Available models as of January 2019 are:Airy
Fenton
Stokes

air_model
The Raschii air model to use, default is
FentonAir
. Available models as of January 2019 are:ConstantAir
FentonAir

wave_length, wave_height
Wave parameters

model_order
The order of the wave model, default is 5. Using 1 will always give Airy waves. Stokes waves are implemented up to order 5, Fenton waves can be calculated for arbitrary order, but order 10 is normally a good compromise between accuracy and speed.

depth, depth_above, ramp_time, still_water_position, current_speed
Same as for AiryWaves

blending_height
Distance used for blending water and air stream functions above the free surface in Raschii, see the Rascii documentation for more details.
ScalarField¶

variable_name
The name of the scalar function that will be exposed, default
phi
.

polynomial_degree
The polynomial degree of the Continuous Lagrange function used to interpolate the field. Default 2

cpp_code
The field description. You can use the coordinate vector,
x[i]
, the time,t
, and any constants given inuser_constants
, see User constants and code.
VectorField¶
Same as scalar field, but cpp_code
must be a list of C++ expressions and
the length of the list must be 2 in 2D and 3 in 3D.
BlendedField¶
All variables, such as phi, are expressed as
where b is the scalar blending function with values [0, 1]

field0, field1
Names of the two known fields to be blended (not field functions, just the name of the field). All field functions of the respective fields are blended.

blending_function
The name of the scalar function used for blending
fields:
 name: x squared
type: ScalarField
cpp_code: pow(x[0], 2)
stationary: true
 name: t squared
type: ScalarField
cpp_code: pow(t, 2)
 name: xtblend
type: BlendedField
field0: x squared
field0: t squared
blending_function: x squared/phi
MaxField and MinField¶
Return the max or min of two fields

field0, field1
Names of the two known field functions
FreeSurfaceZone¶
A field that is 1.0 near the interface and 0.0 away from the interface

variable_name
The name of the scalar function that will be exposed, default
phi
.

radius
The resulting field will be 1.0 inside a distance
radius
from the free surface and 0.0 outside two times the radius. Between these points there will be a smooth transitiontransition = 2 * r ** 3  9 * r ** 2 + 12 * r  4
WaterBlock¶
A block of water, projected to obtain the best representation of the colour field c given a mesh that does not conform to the block. Inside the block the field is 1.0, outside the block it is 0.0. The free surface is projected to be as sharp as possible

variable_name
The name of the scalar function that will be exposed, default
c
.

xmin, xmax, ymin, ymax, zmin, zmax
The extents of the block, all default to 0

polynomial_degree
The polynomial degree of the resulting field, default 0, which gives a piecewise constant field

colour_projection_degree
Project the colour function to DG0 using quadrature of this degree, default 6 (set degree to 1 to prevent this projection and just use interpolation instead)