CMS-Flow:Features

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Surface Roller

Table 1. CMS-Flow cards related to the surface roller

Card Arguments Range Default Description
CALC_ROLLER CHARACTER ON | OFF OFF Turns on or off the surface roller model in CMS.
ROLLER_DISSIPATION_COEFFICIENT REA 0.1 0.05-0.15 Roller dissipation coefficient.
ROLLER_EFFICIENCY_COEFFICIENT REAL 1.0 0.5-1.0 Roller efficiency coefficient.
ROLLER_SCHEME CHARACTER UPWIND1 | UPWIND2 | LAX UPWIND1 Determines the numerical scheme used for the surface roller calculation. UPWIND1 is a first order upwind scheme, UPWIND2 is a second order upwind scheme, and LAX is the second order Lax scheme.

Other Features

Parallelization with OpenMP

Both Intel and AMD processors now are shipping chips with multiple cores/processors (henceforth referred to as "processors") available. CMS-Flow is now configured to make use of these extra processes that are available on newer machines.

Additional information on using Multiple Processors with CMS-Flow can be found here.

Advanced Output

The following advanced cards have been added to CMS v4.0 and higher for outputting additional output information, ASCII file output, and more.

Card Arguments Description Default value
XMDF_COMPRESSION ON | OFF Compresses the h5 file by a factor of about 7 OFF
WAVE_OUT_TIMES_LIST integer Output time series id 0
EDDY_OUT_TIMES_LIST integer Output time series id 0
VISC_OUT_TIMES_LIST integer Output time series id 0
STRESS_OUT_TIMES_LIST integer Output time series id 0
BED_SHEAR_STRESS_OUT_TIMES_LIST integer Output time series id 0
GLOBAL_TECPLOT_FILES ON | OFF Outputs Tecplot ASCII files OFF
GLOBAL_SUPER_FILES ON | OFF Outputs Tecplot ASCII files OFF
GLOBAL_STATISTICS [t0] [tn] [dt] Calculates global statistics if specified none
FLOW_STATISTICS [t0] [tn] [dt] Calculates flow statistics if specified none
SEDIMENT_STATISTICS [t0] [tn] [dt] Calculates sediment statistics if specified none
SALINITY_STATISTICS [t0] [tn] [dt] Calculates salinity statistics if specified none

Matrix solver

The four different solvers implemented in the implicit model are the Gauss-Seidel, Gauss-Seidel with Successive-Over-Relaxation, BICGSTAB, and GMRES. The same solver is applied to flow, sediment and salinity. The default solver is the GMRES. The solver may be changed using the advanced card in the table below.

Card Arguments Description Default value
SOLVER_TYPE GAUSS-SEIDEL | GAUSS-SEIDEL-SOR | BICGSTAB | GMRES Determines the numerical solver used GMRES
HYDRO_MAX_ITER integer Maximum number of iterations (outer loop) for the hydrodynamics 20
SEDIMENT_MAX_ITER integer Maximum number of iterations (outer loop) for the sediment transport 20
SALINITY_MAX_ITER integer Maximum number of iterations (outer loop) for the salinity transport 20

Advection scheme

As in the case of the solver, the same advection scheme is applied for the flow, sediment and salinity transport equations. There are three choices for advection schemes with upwinding in the implicit model: hybrid, exponential and HLPA. The hybrid scheme is fast but is the most diffusive. The exponential scheme is based on the 1D analytical solution to an advection-diffusion equation and produces very stable results. The HLPA is very stable and non-diffusive, but requires slightly more computational time. For most applications, the exponential scheme is recommended and is set as the default. The advection scheme may be change using the advanced card

Card Arguments Description Default value
ADVECTION_SCHEME HYBRID | EXPONENTIAL | HLPA Determines the advection scheme EXPONENTIAL

Units of Measurement

Variable Units Symbol
Water Surface Elevation meters
Current Velocity meters per second
Flow Rate cubic meters per second
Salinity Concentration parts per thousand
Sediment Concentration kilogram per meter cubed
Sediment Transport meter squared per second
Bed Shear Stress kilogram per meter per second squared

CMS-Flow