Section: ABL

This section is for setting atmospheric boundary layer parameters.

ABL.kappa

type: Real, optional, default = 0.41

Wall model coefficient.

ABL.surface_roughness_z0

type: Real, optional, default = 0.1

Wall model surface roughness.

ABL.normal_direction

type: Integer, optional, default = 2

Wall model normal direction. x-direction = 0, y-direction = 1, z-direction = 2.

ABL.log_law_height

type: Real, optional

Height to evaluate the log law for the wall model. Currently, if this parameter is not specified in the input file, the first half cell height is calculated and is used to set the log law height. Therefore the log law height depends on the domain size and number of elements in the normal direction. If this parameter is set to a number the log law is evaluated at a fixed height. Note: currently the fluctuating velocity terms in the shear stress model are only available at the first cell center above the wall. This limitation will be removed soon.

ABL.temperature_heights

type: List of Reals, mandatory

Height(s) in meters at which temperature values are prescribed.

ABL.temperature_values

type: List of Reals (has to be same length as ABL.temperature_heights), mandatory

Temperature values in Kelvin at the corresponding ABL.temperature_heights. The temperature below the first height is assumed to be constant and equal to the first temperature value. The temperature between values is initialized to have linear variation. The final temperature is constant above the last specified height.

ABL.perturb_velocity

type: Boolean, optional, default = true

If true this flag turns on perturbations to the freestream flow.

ABL.pertub_ref_height

type: Real, optional, default = 50.0

Reference height for velocity perturbations, perturbations exist below this height and decay above this height. Only active when ABL.perturb_velocity = true.

ABL.Uperiods

type: Real, optional, default = 4.0

Number of sinusoidal waves in x-direction. Only active when ABL.perturb_velocity = true.

ABL.Vperiods

type: Real, optional, default = 4.0

Number of sinusoidal waves in y-direction. Only active when ABL.perturb_velocity = true.

ABL.deltaU

type: Real, optional, default = 1.0

Amplitude of fluctuations in x-direction. Only active when ABL.perturb_velocity = true.

ABL.deltaV

type: Real, optional, default = 1.0

Amplitude of fluctuations in y-direction. Only active when ABL.perturb_velocity = true.

ABL.perturb_temperature

type: Boolean, optional, default = false

Perturb temperature field with random fluctuations.

ABL.theta_amplitude

type: Real, optional, default = 0.8 K

Amplitude of the temperature perturbations added to the initial field. Only active when ABL.perturb_temperature is true.

ABL.cutoff_height

type: Real, optional, default = domain height

Height below which temperature perturbations are added

ABL.random_gauss_mean

type: Real, optional, default = 0.0

Mean for the Gaussian random number generator

ABL.random_gauss_var

type: Real, optional, default = 1.0

Variance for the Gaussian random number generator

ABL.bndry_file

type: String, optional, default = “”

NetCDF-4 file name for ABL inflow

ABL.bndry_io_mode

type: Int, optional, default = -1

IO mode (0=output, 1=input)

ABL.bndry_planes

type: String, optional, default = “”

IO planes for ABL inflow

ABL.bndry_output_start_time

type: Real, optional, default = 0.0

Time at which to start ABL inflow output

ABL.bndry_var_names

type: String, optional, default = “”

Variables for IO for ABL inflow

ABL.wall_shear_stress_type

type: String, optional, default = “Moeng”

Wall shear stress model: options include “constant”, “local”, “Schumann”, and “Moeng”

ABL.initial_condition_input_file

type: String, optional, default= “”

File that contains initial conditions for the velocity field in netcdf file format. This file is expected to have the same dimensions as the simulation. Values are passed directly from the file to the velocity field inside the code. Only spanwise velocity components are supported.

ABL.anelastic

type: Boolean, optional, default= false

Activate anelastic behavior. This adds reference_density and reference_pressure fields.

ABL.bottom_reference_pressure

type: Real, optional, default = 1.01325e5

Reference pressure at the bottom of the domain. Used for anelastic ABL.