The CMS-Flow Model Control dialog allows the user to view and edit the current parameters that affect how CMS-Flow runs and what options are to be included in the current simulation. The dialog includes nine tabs which partition the parameters into related groups. The tabs and their related parameters include:
Flow
CMS-Flow Model Control dialog
This dialog allows the user to specify general flow model parameters, controlling which model options the simulation will employ. The controls include:
Time Control
In this section the user can set the starting time, duration and hydraulic time step. The Ramp duration defines the length of an incremental loading portion at the beginning of the simulation. Controls include:
Start date and time
Simulation duration or end date and time
Ramp duration
Hot Start
These controls allow the user to specify a previously saved hot start file to be used as initial conditions or instruct CMS-Flow to save hot start files for future use.
Initial conditions file
Write Hot Start output file
Time at which Hot Start output file should be written
CMS-Flow can take advantage of multiple processors using Open-MP parallelization technology. This control allows the user to specify the maximum number of threads that the engine should occupy.
Water Parameters
Water temperature
Water density
Parameters
Depth to begin drying cells
Include wall friction
Latitude throughout grid
Cell specific latitude
Average latitude
Momentum Equation
Include advective terms
Include mixing terms
Solution Scheme
CMS-Flow now has two solution schemes. These include the traditional "explicit" scheme. This method requires that flow be tracked through each element, resulting in hydrodynamic time steps in the order of one to two seconds. The new option is an "implicit" scheme which uses finite volume technology, supports much larger time steps resulting in fewer time steps (shorter run times) and is identically mass conserving.
When the implicit scheme is being used, one of the following matrix solver types should be specified.
GMRES
GAUSS-SEIDEL
GAUSS-SEIDEL-SOR
BICGSTAB
Sediment
CMS-Flow Model Control dialog showing the Sediment tab
Time steps
Transport rate
Morphologic
Sediment
Calculate sediment transport
Use non-equilibrium transport
Formulation
Advection-diffusion
Hard Bottom
Create Dataset
Select Dataset
Delete Dataset
D50
Create Dataset
Select Dataset
Delete Dataset
Salinity
CMS-Flow Model Control dialog showing the Salinity tab
This tab allows the user to specify model parameters relating to salinity modeling in CMS-Flow. The controls include:
Salinity
CMS-Flow includes the capability to simulate the diffusion of saline water in fresh water. This section includes controls to enable and initialize these calculations.
Calculate salinity – Turn on the calculation of salinity concentrations in the CMS-Flow simulation.
Time Steps
In addition to the time step specified in the general parameters tab for hydrodynamic calculations, the explicit model also allows the specification of longer time step for the salinity dispersion process.
Transport rate – If salinity is enabled in this tab, and the solver option is set to "explicit" in the Flow tab, the user must specify a this time step. It must be larger than the hydrodynamic time step and is generally at least a factor of 20. The default transport rate time step is 60 seconds.
Initial Condition
Salinity transport requires that each cell have an initial value for salinity concentration (measured in ppt). CMS-Flow allows this value to start as a constant for each cell, in which case, during the initial (or ramp time)of the simulation the concentrations are distributing to natural values.
Global concentration – This control allows the user to specify an initial concentration for the entire domain. The value 0.0 ppt (fresh water) is a commonly used value.
Spatially varied – these controls allow the user to create or select a spatially varied dataset that will be used by CMS-Flow as the initial concentration at each cell. This dataset is editable by the user.
Create Dataset
CMS-Flow Salinity Global Concentration dialog
Select Dataset
Delete Dataset
External Documentation
Two-Dimensional Depth-Averaged Circulation Model CMS-M2D: Version 3.0, Report 2, Sediment Transport and Morphology Change[1]
Tidal
CMS-Flow Model Control dialog showing the Tidal tab
Flow
This dialog allows the user to specify general hydrodynamic or flow model parameters, controlling which model options the simulation will employ. The controls include:
Hydrodynamic Time Step
This control allows the user to set the hydrodynamic time step for the model. If the explicit solution scheme is being used, a recommended timestep will be calculated based on grid cell size and depths.
Water Parameters
This section allows the user to specify various general parameters to be used by the simulation. This include:
Water temperature
Water density
Depth to begin drying cells: This is a minimum depth of water before the model considers the cell to be dry. Shutting off cells when the depth drops below a tolerance avoids flutter of insignificant transfers of water. The recommended default value is 0.05 meters.
Include advective terms
Include mixing terms
Include wall friction: Normally friction at the closed boundaries are ignored. The model can be instructed to include friction along these boundaries as if a wall exists there.
Include stokes velocities
Bottom Friction Dataset
Friction datasets can be created and specified to define a spatially variable bottom roughness to provide a resistance to flow. This value has little impact in deep ocean applications but can be important in shallow regions. This is a user editable dataset. The available dataset types are:
Mannings N
Bottom friction coefficient
Roughness height
A bed-slope friction coefficient toggle gives the option to specify a wave-current bottom friction type and a coefficient.
CMS-Flow Model Control dialog showing the Wind/Wave tab
This dialog allows the user to specify wind conditions. These are optional inputs to the engine.
Wind Data
The user can turn on the option to tell CMS to include wind calculations in the simulation. Wind is simulated in CMS-Flow as a spatially constant, but temporally varying quantity. The model does not currently support tropical cyclonic winds.
Spatially constant
Import from File...: Button allowing the user to import wind data from a file. The file must be in an "m2w" wind format.
Velocity (m/s): Button which invokes a time series editor to specify the variation of wind velocity through time in the simulation.
Direction (deg): Button which invokes a time series editor to specify the variation in direction of the wind through time in the simulation.
Anemometer height (m)
Meteorologic stations – This option allows the user to insert data for multiple locations
Import from File...: Button allowing the user to import wind data from a file. The file must be in an "m2w" wind format.
Coordinates (X,Y): Location of meteorologic station
Velocity (m/s): Button which invokes a time series editor to specify the variation of wind velocity through time in the simulation.
Direction (deg): Button which invokes a time series editor to specify the variation in direction of the wind through time in the simulation.
Anemometer height (m)
Temporally and spatially varying from file
Navy fleet numeric with pressure
OWI/PBL
Single ASCII file
Navy fleet and ASCII files require the following input:
CMS-Flow includes three options on how to use wave data.
None – no wave data is imputed into the model.
Single wave condition – the effects of waves are input to the model in the form of spatially varying datasets. These datasets must already exist on the grid. The user simply selects which dataset to use
Height
Period
Direction
Dissipation
Stress gradients (vector dataset)
Surface roller stress gradients (optional)
Inline steering
CMS-Wave file. Location of the grid file or the simulation file
Steering Interval or automatic value
Specify extrapolation distances. If checked this will write out FLOW_EXTRAPOLATION_DISTANCE and WAVE_EXTRAPOLATION_DISTANCE cards.
Wave Water Level – Option to select Tidal, Last, or Tidal plus variation (default value).
Output
CMS-Flow Model Control dialog showing the Output tab
This dialog allows the user to specify global output options for the simulation. This controls the datasets created by the engine which consist of spatially and temporally varied quantities (values per cell at each output time value).
These output datasets are stored in an XMDF solution file.
Output Times Lists
Due to the potentially long simulation times, CMS-Flow does not output at a constant interval during the simulation. Instead, the user defines one or more lists of times. For each dataset output by the engine, the user selects one time list. The selected quantity will be saved at each time in the time list.
Lists: CMS-Flow supports up to four different and individual sets of time values.
Output Times: The times included in the selected time list are displayed in this window.
Type: The user adds and removes times to/from a time list using the tools in the time type section.
Output Datasets
CMS-Flow can output each of the following datasets. For each group, a time list must be specified. The optional datasets may turned off/on by clicking on their checkboxes in the output dataset tree.
Water surface elevation
Velocity
Current Magnitude (optional)
Current Velocity
Morphology
Depth (through time)
Morphology Change (optional)
Transport
Sediment Total-Load Concentration (optional)
Sediment Total-Load Capacity (optional)
Fraction Suspended (optional)
Total Sediment Transport
Salinity Concentration (optional)
Waves
Wave Height
Wave Period
Wave Height Vector
Wave Dissipation (optional)
Wind
Wind Speed (optional)
Wind Speed Vector
Eddy Viscosity
Statistical Output
Statistical data can be written out for hydrodynamics, sediment transport, and salinity. This option is turned on by toggles, and a start time, increment, and end time must be specified.
Output Options
Output can be written out in ASCII format and using XMDF file compression. These options are turned on by toggle boxes. All datasets created by the model will be labeled with a simulation label and quantity label. An edit field allows specification of the simulation label.
Cells
CMS-Flow Model Control dialog showing the Cells tab
Time Series Observation Output
U velocity
V velocity
Water surface (ETA)
Output interval
Row Rate Observation Output
X direction
Y direction
Output interval
Transport Observation Output
X direction
Y direction
Output interval
Input
CMS-Flow Model Control dialog showing the Input tab
Bottom Friction Dataset
Manning's n
Bottom friction coefficient
Roughness height (m)
Create Dataset
Select Dataset
Delete Dataset
Custom Input Datasets
Advanced Options
CMS-Flow Model Control dialog showing the Advanced tab
This dialog allows the user to specify experimental options when working with the model developers.
Advanced Cards
Model options not available in the interface can be specified in the CMS-Flow model control under the advanced tab. Each row in the spreadsheet will be saved as a different line in the *.cmscards file. The cards can be inserted and deleted using the insert and delete rows.
The lines will be written out exactly as typed.
The lines will be written out in the order in which they appear in the dialog.
Any lines encountered in a *.cmscards file that is not recognized will appear in this list.
Lines beginning with a "!" character are treated as comment lines and will be skipped over during a read.
Comment lines are automatically generated and will not be preserved.
All of these advanced cards will be grouped together at the bottom of the file regardless of where they appeared during reading.
