Section: Ocean Waves
This section is for setting up wave forcing and relaxation zones.
- OceanWaves.label
type: String
Name for Ocean Waves instance. As a placeholder, the label ‘label’ will be used in this documentation.
- OceanWaves.label.type
type: String
Type of wave to be used. Options include LinearWaves, StokesWaves, and W2AWaves. Linear and stokes waves are monochromatic waves. W2AWaves uses the Waves2AMR library to read and transform HOS-Ocean wave data into the AMR-Wind domain, and this option requires the Waves2AMR library (abbreviated W2A) to be enabled at compile time.
- OceanWaves.label.relax_zone_gen_length
type: Real, optional, default = 4.0
Length of region, in x-direction, over which the wave profile will be forced. The region begins at the low x boundary and extends in the positive x direction, covering the entire width of the domain in the y direction and applying to all liquid at all depths (in z). Always on, even if argument is not specified.
- OceanWaves.label.numerical_beach_length
type: Real, optional, default = 8.0
Length of region, in x-direction, over which the waves will be forced to a flat interface. The region begins at the high x boundary and extends in the negative x direction, covering the entire width of the domain in the y direction and applying to all liquid at all depths (in z). Always on, unless relax_zone_out_length is included in the input file.
- OceanWaves.label.numerical_beach_length_factor
type: Real, optional, default = 1.0
Length factor for numerical beach region. Following the formulation suggested by Chen, Kelly, and Zang (2019), this factor increases the effective length of the numerical beach while keeping it as the same physical length. This approach stems from the observation that waves are typically fully absorbed in the first half of the numerical beach, leaving the second portion basically unused. Therefore, using a numerical beach length factor can reduce the size of the required domain while still achieving the same results. For example, if a numerical beach length of 2 wave lengths is needed,
numerical_beach_lengthcould be set to 1 wave length, and thennumerical_beach_length_factorwould be set to 2.
- OceanWaves.label.relax_zone_out_length
type: Real, optional, default = 8.0
Length of region, in x-direction, over which the wave profile will be forced. This input argument replaces, and thereby turns off, the numerical beach. The region begins at the high x boundary and extends in the negative x direction, covering the entire width of the domain in the y direction and applying to all liquid at all depths (in z). Only on when included in the input file.
- OceanWaves.label.zero_sea_level
type: Real, optional, default = 0.0
Default location (in z) of the liquid surface. Where the water would rest in the absence of waves.
- OceanWaves.label.water_depth
type: Real, optional, default = 0.5
The depth of the water in the simulation, used for calculating analytical wave profiles (linear and stokes waves). Should be equal to the difference between the zero_sea_level and the low z boundary location.
- OceanWaves.label.timeramp_period
type: Real, optional
An initial ramp-up period for the wave forcing. Without specifying a period, the wave forcing will begin at full strength.
- OceanWaves.label.initialize_wave_field
type: Boolean, optional, default = false
By default, the domain will be initialized with a flat interface; if this option is turned on, the wave profile will be initialized over the entire domain. If there is a specified relax_zone_out_length, this option is automatically turned on.
The following input arguments are only valid for the LinearWaves and StokesWave wave types:
- OceanWaves.label.wave_length
type: Real, mandatory
The wave length of the wave profile. This argument can be omitted for Stokes waves if the wave period is provided instead.
- OceanWaves.label.wave_height
type: Real, mandatory
The amplitude of the wave profile
The following input arguments are only valid for the StokesWave wave type:
- OceanWaves.label.order
type: Integer, mandatory
The order of the Stokes wave formula being used. All Stokes wave theory (wave profile and dispersion relation) is applied from Fenton (1985). The minimum order is 2, and the maximum order is 5.
- OceanWaves.label.wave_period
type: Real, optional
If the wave period is provided and the wave length is not, the wave length will be solved iteratively using the wave height, the wave period, and the Stokes waves dispersion relation. If the wave length is not provided, this argument becomes mandatory.
- OceanWaves.label.stokes_wavelength_order
type: Real, optional
Specifies the order of the dispersion relation used to calculate the wave length. By default, this is equal to the
orderof the waves. Practically, the minimum value is 1, and the maximum is 5.
- OceanWaves.label.stokes_wavelength_tolerance
type: Real, optional, default = 1e-10
Convergence tolerance of the iterative process to calculate the wave length.
- OceanWaves.label.stokes_wavelength_iter_max
type: Integer, optional, default = 40
Maximum number of iterations during the process to calculate the wave length.
The following input arguments are only valid for the W2AWaves wave type:
- OceanWaves.label.HOS_modes_filename
type: String, mandatory
The name of the modes file, output by HOS-Ocean, in the SWENSE format.
- OceanWaves.label.HOS_init_timestep
type: Integer, optional, default = 0
The time step in the modes file for the AMR-Wind simulation to start at.
- OceanWaves.label.HOS_init_time
type: Integer, optional, default = 0
The physical time in the modes file for the AMR-Wind simulation to start at. This argument is only active if HOS_init_timestep is omitted. AMR-Wind will pick the time step in the modes closest to the specified time.
- OceanWaves.label.fftw_planner_flag
type: String, optional, default = estimate
When setting up a plan for the inverse Fourier transform within the Waves2AMR library, the FFTW algorithm can use different techniques to choose among available methods. Some of these are faster than others, and the optimal choice can also depend on the architecture. The default, “estimate”, which corresponds to FFTW_ESTIMATE, is deterministic. The other options are “exhaustive”, “patient”, and “measure”. Variations from nondeterministic approaches are tiny, on the order of machine precision.
- OceanWaves.label.number_interp_points_in_z
type: Integer, mandatory
When Waves2AMR converts mode data to spatial data, the z locations to perform the transformation must be chosen. AMR-Wind does this by creating a geometric series from the water surface to the lower z boundary, starting with a small spacing between points near the surface and then expanding downward. This argument is the total number of z locations where wave modes will be transformed to inform the wave velocity field. After the transformation step, the data is then interpolated to the AMR-Wind mesh. More points means better resolution over the whole depth, but more points also means more work for the solver.
- OceanWaves.label.interp_spacing_at_surface
type: Real, mandatory
The physical spacing between interpolation points at the water surface. This is the most influential parameter for the geometric series that dictates the location of the points in z. This should be set to near the mesh spacing in z around the water surface.
- OceanWaves.label.number_interp_above_surface
type: Integer, optional, default = 1
The number of points placed above the mean water surface for the velocity transformation process. The spacing between the points above the surface is equal to the
interp_spacing_at_surface. When setting this value, the wave height should be considered so that velocity can be accurately computed for portions of the waves above the mean surface.