CMS-Flow Multiple-sized Sediment Transport

Figure 1. CMS-Flow Model Control : Model Parameters tab in SMS 11.0.

All of the CMS-Flow model parameters, settings, and output options are controlled from the CMS-Flow Model Control window (Figure 1). The window has several tabs including the Flow tab in which most of the general settings are set for CMS-Flow. To open the CMS-Flow Model Control window, click on CMS-Flow | Model Control. The first tab will be the Flow tab. There are several sections within the tab including Time Control and Hot Start options.

Grain Size Specification

Card	Arguments	Example	Description
SEDIMENT_SIZE_CLASS_NUMBER	INTEGER	3	Specifies the number of grain size classes.
MULTIPLE_GRAIN_SIZES	INTEGER [REAL, REAL,..., REAL]	3 0.1 0.2 0.3	Specifies the number of grain sizes followed by the grain sizes for each size class in mm.
SEDIMENT_SIZE_CLASS_DIAMETERS	INTEGER [REAL, REAL,..., REAL]	3 0.1 0.2 0.3	Specifies the number of grain sizes followed by the grain sizes for each size class in mm. Same as ULTIPLE_GRAIN_SIZES.
SEDIMENT_SIZE_CLASS_LIMITS	INTEGER [REAL, REAL,..., REAL]	4 0.07 0.15 0.26 0.34	Specifies the size classes limits. The first entry is the number of size class limits which is one greater than the number of size classes.

D50 Dataset and Standard Deviation

This is the simplest and easiest way to specify the bed composition for multiple-sized sediment transport in CMS because it only requires the D50 dataset which is already in the SMS interface and one extra parameter, the geometric standard deviation.

• Assumptions:

1. The initial sediment sorting is constant for the whole domain
2. The initial bed composition may vary spatially according to the D50 dataset but is constant with depth
3. The initial grain size distribution can be approximated by a log-normal distribution

Card	Arguments	Default/Format	Description
D50_DATASET	CHARACTER CHARACTER | CHARACTER	[file name] [dataset path and name]	Specifies the D50 dataset file followed by the path and name. If the file name is not specified than it is assumed to be the grid file (*_grid.h5).
SEDIMENT_STANDARD_DEVIATION	REAL	1.5	Specifies the geometric sediment standard deviation for all cells and layers in mm.

Fractional Bed Composition

This option is useful for simulating cases where the bed composition is well known and is constant both in the horizontal and vertical directions.

• Assumption:

1. The initial bed composition is constant at every cell and layer for whole domain

Card	Arguments	Default/Format	Range	Description
BED_COMPOSITION_INPUT	CHARACTER	D50_SIGMA | D16_D50_D84 | D35_D50_D90 | SIZE_CLASS_FRACTIONS | FRACTIONS_DATASET	Selects the method for specifying the bed material composition.

D16, D50, and D84 Datasets

• Assumptions:

1. The initial bed composition may vary spatially according to the D16, D50, and D84 datasets but is constant with depth
2. The initial grain size distribution can be approximated by a log-normal distribution

Card	Arguments	Default/Format	Description
D16_DATASET	CHARACTER CHARACTER	[file name] [dataset path and name]	Specifies the D16 dataset path and file name.
D50_DATASET	CHARACTER CHARACTER | CHARACTER	[dataset path and name] | [file name] [dataset path and name ]	Specifies the D50 dataset path and file name. If the file is not specified than it is assumed to be the model parameters file name (*_mp.h5).
D84_DATASET	CHARACTER CHARACTER	[file name] [dataset path and name]	Specifies the D50 dataset path and file name.
CUSTOM_DATASET	CHARACTER CHARACTER	[file name] [dataset path and name]	Specifies a custom dataset path and file name. The custom dataset can be used for any additional user defined dataset. The name of the dataset must be equal to the variable name. For example the D16 dataset must be named D16 and cannot be myD16.

Custom Datasets

The first approach of specifying the D16 and D84 datasets is by using the Custom Input Datasets section under the Input tab of the CMS-Flow Model Control window. The advantage of using this approach is that the user can edit the datasets once they are created without having to map each dataset as the Elevation dataset. It also avoids having to specify the dataset files and names manually in the *.cmcards file. The steps for creating and specifying the D16 and D84 datasets are outlined below:

1. Open CMS-Flow Model Control window and go to the Input tab.
2. To create the D16 dataset, click on the New buttom and a window will appear titled New Editable Dataset.
3. Name the dataset D16 for the D16 dataset or D84 for the D84 dataset. The names must be correct for CMS to be able to interpret the dataset.
4. Set the initial values by either specifying a spatially constant value or selecting a current dataset.
5. Click OK in the New Editable Dataset window
6. Repeat steps 2 through 5 for the D84 dataset.
7. Click OK in the CMS-Flow Model Control window
8. Save the CMS-Flow project

Figure 2. Creating Custom Datasets for D16 and D84.

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

Once the datasets are created the SMS project explorer will show a folder with the D16 and D84 datasets.

After saving the CMS-Flow project the project folder will show a new dataset called Flow_Shark_input_datasets.h5 (see Figure below).

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

The data structure of the Flow_Shark_input_datasets.h5 file is shown in the Figure below.

Figure 3. Structure of the Custom Input Datasets file shown in XMDFView.

Exported Datasets

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

An alternate approach for specifying datasets is by exporting them into XMDF files and then specifying the file names and paths in the Advanced cards section of the *.cmcmards file. The advantage of this approach is that is allows more flexibility in specifying project alternatives and also works for SMS versions 10.1 and earlier.

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

Figure 3. SMS project explorer showing Custom Datasets for D16 and D84.

D35, D50, and D90 Datasets

• Assumptions:

1. The initial bed composition may vary spatially according to the D16, D50, and D84 datasets but is constant with depth
2. The initial grain size distribution can be approximated by a log-normal distribution

Card	Arguments	Default/Format	Range	Description
D35_DATASET	CHARACTER	none
D50_DATASET	CHARACTER	none
D90_DATASET	CHARACTER	none

Size Class Fractions

For this case, the fractional bed compositions are specified for each size class for all cells and all bed layers. The fractional bed compositions must sum to 1.0.

Card	Arguments	Example	Description
SEDIMENT_SIZE_CLASS_FRACTIONS	INTEGER [REAL, REAL,..., REAL]	3 0.2 0.5 0.3	Specifies the fractional composition for each size class for all cells and bed layers. The first entry is the number of grain size classes.

Fractional Composition Dataset

Card	Arguments	Default/Format	Range	Description
BED_FRACTIONAL_COMPOSITION_DATASET	CHARACTER CHARACTER	[<grid file>] [<grid name>//"Datasets/<Name>"]	Fractional bed composition file. Necessary when setting BED_COMPOSITION_INPUT to FRACTION_DATASET.

Bed Layer Thickness

Table 1. CMS-Flow cards related to the general parameters

Card	Arguments	Default/Format	Range	Description
BED_LAYER_THICKNESS_INPUT	CHARACTER	NONE	NONE | CONSTANT | LAYER_THICKNESS | LAYER_DATASET
BED_LAYER_THICKNESS_DATASET	CHARACTER CHARACTER	none	[file] [path]	Specifies the bed layer thickness file and dataset path.
BED_LAYERS_MAX_NUMBER	INTEGER
BED_LAYERS_CONSTANT_THICKNESS	INTEGER [REAL, REAL,..., REAL]
BED_LAYERS_THICKNESS	INTEGER [REAL, REAL,..., REAL]
BED_LAYERS_CONSTANT_THICKNESS	INTEGER [REAL, REAL,..., REAL]
BED_LAYERS_CONSTANT_THICKNESS	INTEGER [REAL, REAL,..., REAL]

Mixing Layer

Card	Arguments	Default/Format	Range	Description
MIXING_LAYER_CONSTANT_THICKNESS	INTEGER [REAL, REAL,..., REAL]
MIXING_LAYER_MIN_THICKNESS	INTEGER [REAL, REAL,..., REAL]

Parameters

The general parameters are the water density and temperature. The CMS-Flow cards for the general parameters are described in the table below.

Card	Arguments	Default/Format	Range	Description
HIDING_EXPOSURE_COEFFICIENT	REAL	1025	-	Water density in kg/m^3.
HIDING_EXPOSURE_COEFF	REAL	15	-	Water temperature in degrees Celcius.

Boundary and Initial Conditions

Card	Arguments	Default/Format	Range	Description
SEDIMENT_INFLOW_LOADING_FACTOR	REAL	1025	-	Water density in kg/m^3.
SEDIMENT_FLUX_CELLSTRING	REAL	1025	-	Water density in kg/m^3.

Output Files and Datasets

Card	Arguments	Default/Format	Range	Description
BED_OUT_TIMES_LIST	INTEGER	1025	-	Water density in kg/m^3.
SEDMIX_OUT_TIMES_LIST	INTEGER	1025	-	Water density in kg/m^3.

Examples

• Example 1

SEDIMENT_MAX_ITERATIONS             30    
SEDIMENT_STATISTICS                 120.0 720.0    
BED_COMPOSITION_INPUT               D50_SIGMA       
MULTIPLE_GRAIN_SIZES                6 0.1 0.126 0.16 0.2 0.25 0.31
SEDIMENT_STANDARD_DEVIATION         1.3       
BED_LAYER_CONSTANT_THICKNESS        0.5       
MIXING_LAYER_CONSTANT_THICKNESS     0.1      
MIXING_LAYER_MIN_THICKNESS          0.05      
HIDING_EXPOSURE_COEFFICIENT         1.0       
SEDMIX_OUT_TIMES_LIST               2    
BED_OUT_TIMES_LIST                  2    
CALC_MORPH_DURING_RAMP              OFF   

• Example 2

SEDIMENT_MAX_ITER                   30 
BED_COMPOSITION_INPUT               D50_SIGMA  
SEDIMENT_STANDARD_DEVATION          1.5
MULTIPLE_GRAIN_SIZES                5 0.08 0.12 0.17 0.28 0.45
BED_LAYER_CONSTANT_THICKNESS        0.5
MIXING_LAYER_CONSTANT_THICKNESS     0.02       
MIXING_LAYER_MIN_THICKNESS          0.01 

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