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.
RMA2 model parameters are divided into the following groups in the RMA2 Model Control:
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 simulation - 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
