SMS:RMA2 Model Control Dialog

This article highlights frequently used RMA2 model control parameters. Please see the RMA2 model documentation for a description of items not discussed or for more information on specific items. Model parameters are set in the RMA2 Model Control dialog access through the RMA2 | Model Control menu command.

RMA2 model parameters are divided into the following groups in the RMA2 Model Control dialog:

General

RMA2 Model Control dialog showing the General tab

Simulation Titles / $T1 Card

The RMA2 .geo file contains three comment lines, which can be set using the Title 1, Title 2, and Title 3 edit fields.

Machine Type / $M Card

Set the machine type the RMA2 simulation will be run on. Options include:

• Microprocessor (PC) – Default option. Direct access record length is unlimited and is define in terms of bytes.
• Prime mini-computer – Direct access record length is unlimited and is defined in terms of small words (i.e. 2 bytes).
• DEC VAX – Direct access record length, limited to 32K bytes and defined in terms of long words (4 bytes).
• Cray or Cyber-205 – Direct access defined for systems using 64 bit or 8 byte words and where record lengths are defined in bytes.
• HP or Alpha workstations – Direct access defined using multiple sequential access files that are opened as required.

Water Properties

Set the properties of the water being simulated.

• Temperature / FT Card – Average initial water temperature.
• Density / FD Card – Used to supply a fluid density for all nodes or a specified node.
• Coldstart initial water surface / IC Card – Used to provide initial conditions to start a cold run.
• 1D node initial conditions
  • Minimum depth / IC Card – Minimum depth used for one-dimensional nodes at startup.
  • Initial velocity / IC Card – Nominal velocity for one-dimensional nodes.

Scale Factors

• X scale / GS Card – Scale factor for X-coordinates.
• Y scale / GS Card – Scale factor for Y-coordinates.
• Z scale / GS Card – Scale factor for Z-coordinates (bottom elevation).

Model Stability

• Special calculations

Timing

RMA2 Model Control dialog showing the Timing tab

Simulation Type

• Steady state – Boundary conditions do not change with time. A "snapshot" in time.
• Dynamic – Boundary conditions change with time. Computation time parameters will need to be specified.

Iterations For Flow Calculations

See the TI Card description in the RMA2 model documentation.

• Initial solution – Maximum number of iterations to perform for the initial solution.
• Each time step – Used for dynamic simulations. Sets the maximum number of iterations to perform after the first time step.

Computation Time

See the TZ Card description in the RMA2 model documentation.

• Time step size – DELT Variable
• Number of time steps – NCYC Variable
• Maximum time – TMAX Variable
• First time step – NSTART Variable
• Perform intermediate restart – MBAND Variable

Bendway Correction

Used to supply values associated with the calculation of vorticity. See the VO Card description in the RMA2 model documentation.

• Compute vorticity – IVOR Variable
• ASEC – ASEC coefficient for the vorticity equation. Recommend: 5.0
• DSEC – DSEC coefficient for the vorticity equation. Recommend: 0.5
• RCMIN – Minimum radius of curvature that will be allowed. Recommend: 6 feet (or 2 meters).

See also BV card, TV card.

Depth Convergence Parameters

• Steady state depth convergence
• Dynamic depth convergence

Vorticity Convergence Parameters

See the VO Card description in the RMA2 model documentation.

• Steady state vorticity convergence
• Dynamic vorticity convergence

Iterations for Vorticity Calculations

The maximum number of iterations allowed for the vorticity calculation is set by tvariables NVITI or NVITN on the TV card. If the number of passes between the phases reaches NPASS1 or NPASS2, then the calculation has failed to converge. If the number of “good passes” between the two phases exceeds NGOODMAX, the calculation is finished and the code can proceed to the next time step. See the "Bendway Correction (Vorticity)" section and TV Card description in the RMA2 model documentation.

The following TV Card variables are used to control the number of iterations for vorticity calculations:

• Steady state passes – NPASS1 Variable
• Steady state vorticity iterations – NVITI Variable
• Dynamic passes – NPASS2 Variable
• Dynamic vorticity iterations – NVITN Variable
• Number of good passes required – NGOODMAX Variable

Files

RMA2 Model Control showing the Files tab

RMA2 Input Files

• Specify geometry file – Select an existing RMA2 ASCII Geometry (*.geo) file to use with the simulation
• Hotstart input file – Specify an existing RMA2 Hot Start File (*.hot) to use with the simulation
  • Use specific time for hotstart
• Alternate dynamic BC file – See the "RMA2 Alternate Dynamic BC File Format" section of the RMA2 model documentation
• Write dynamic memory file – See the "Dynamic Memory Allocation" section of the RMA2 model documentation

RMA2 Solution Files

• Write RMA2 solution file
  • Write frequency in time steps
• Write hot start file – Write an RMA2 Hot Start Output (*.hot) file. See RMA2 Spindown for a discussion of hot starting.
  • Save only the last time step – Write only the last successful RMA2 time step solution to the hot start file.
  • Write frequency in time steps – Write multiple time steps to the hot start file.

Informational Files

• Echo card input to screen
• Write ASCII results file
  • Do not echo any node/element input data
  • Echo all input data except initial conditions
  • Echo all input data
  • Write frequency of nodal results in time steps
  • Trace subroutines level
• Write summary by node file
• Write automatically computed parameters file
• Write vorticity file
  • Write frequency in time steps

Global Methods

RMA2 Model Control dialog showing the Global Methods tab

Global Wet/Dry Technique

See the Material Properties article for a description of the Marsh Porosity parameters.

• Elemental wet/dry check
  • Check frequency in timesteps
  • Dry depth
  • Active depth
• Nodal Transition (Marsh Porosity)
  • Options – Opens the Nodal Transition (Marsh Porosity) dialog

Global Roughness Assignment

• Default roughness value
• Roughness by depth
  • Options – Opens the Roughness Options dialog

Coriolis Forces

• Latitude

Global Eddy Viscosity Assignment

See the Material Properties article for a description of the Turbulence parameters.

• Traditional eddy viscosity approach (default)
• Peclet Number
• Smagorinski Method
  • Exx ratio
  • Eyx ratio
  • TBFACTS
  • TBMINFS
  • Peclet Number
  • Minimum velocity

Weather

RMA2 Model Control dialog showing the Weather tab

Wind

According to the RMA2 model documentation, "Because of lack of experience in using storms in a simulation, this feature remains experimental."

See the "Simulating With Storms" section and BWC Card description in the RMA2 model documentation for more information.

• Method for wind
  • Do not use wind
  • Original RMA2 Formula
  • Van Dorn Formula
  • Wu Formula
  • Safaie Formula
  • Ekma Formula
  • Generic Formula
• A
• exp
• C
• rho
• Specify global wind
  • Define – Opens the Wind Values dialog.

Wind Values dialog

Rainfall/Evaporation / RA Card

See the "Adding Rainfall And Evaporation" section and RA Card description in the RMA2 model documentation [1] for more information.

• Specify rainfall or evaporation
  • Define – Opens the Rainfall Values dialog

Related Topics

• RMA2