CMS-Flow Bottom Friction: Difference between revisions
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==Overview== | ==Overview== | ||
In SMS versions 10.1 and earlier, the bottom roughness is specified using the Manning's n coefficient in the ''Cells'' tab of the ''CMS-Flow Model Control'' window (see Figure | In SMS versions 10.1 and earlier, the bottom roughness is specified using the Manning's n coefficient in the ''Cells'' tab of the ''CMS-Flow Model Control'' window (see Figure 1). In SMS 11.0, the option is provided to use a roughness height, or bottom friction coefficient in addition to the Manning's coefficient. In SMS 11.0 the bottom roughness is specified in the ''Bottom Friction Dataset'' section of within the ''Input'' tab of the ''CMS-Flow Model Control'' window (see Figure 2). The ''Bottom Friction Dataset'' is specified at every computational (ocean) cell and is required for each model simulation. | ||
[[image:SMS10p1_CMS-Flow_Model_Control-Cells_Tab.png|thumb|left|500px| Figure | [[image:SMS10p1_CMS-Flow_Model_Control-Cells_Tab.png|thumb|left|500px| Figure 1. Specification of Manning's n coefficient in the ''Cells'' tab of the ''CMS-Flow Model Control'' window in SMS 10.1]] | ||
[[image:CMS-Flow_Model_Control-Input_Tab.png|thumb|none|500px| Figure | [[image:CMS-Flow_Model_Control-Input_Tab.png|thumb|none|500px| Figure 2 Specification of the ''Bottom Friction Dataset'' the ''Input'' tab of the ''CMS-Flow Model Control'' window in SMS 11.0]] | ||
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== Creating a Bottom Friction Dataset == | == Creating a Bottom Friction Dataset == | ||
[[image:CMS-Flow_Project_Explorer_Bottom_Friction.png|thumb|left|600px|Figure 2.3. Three SMS Project Explorer showing the Manning's n, Bottom Friction Coefficient and Roughness Height datasets.]] | [[image:CMS-Flow_Project_Explorer_Bottom_Friction.png|thumb|left|600px|Figure 2.3. Three SMS Project Explorer showing the Manning's n, Bottom Friction Coefficient and Roughness Height datasets.]] | ||
Revision as of 18:46, 17 January 2011
Overview
In SMS versions 10.1 and earlier, the bottom roughness is specified using the Manning's n coefficient in the Cells tab of the CMS-Flow Model Control window (see Figure 1). In SMS 11.0, the option is provided to use a roughness height, or bottom friction coefficient in addition to the Manning's coefficient. In SMS 11.0 the bottom roughness is specified in the Bottom Friction Dataset section of within the Input tab of the CMS-Flow Model Control window (see Figure 2). The Bottom Friction Dataset is specified at every computational (ocean) cell and is required for each model simulation.
Creating a Bottom Friction Dataset
In SMS 11.0 each time a new CMS-Flow simulation is created a bottom friction (roughness) dataset needs to be created using the Create Dataset button. The bottom friction parameter (related to Manning ) is spatially varying (cell-specific) over the grid domain. The default value upon grid creation is 0.025. At times a user may desire to represent locations where added friction is needed due to structures or increased turbulence due to sharp changes in current speed. More information on using this feature of CMS-Flow can be found here.
Table 1. SMS Cards related to the bottom friction
| Card | Arguments | Default | Range | Description | Versions |
|---|---|---|---|---|---|
| USE_WALL_FRICTION | CHARACTER | ON | ON | OFF | Turns on or off wall friction | >=3.5 |
| MANNING_N_DATASET | CHARACTER CHARACTER | [<grid file>] [<grid name>//"Datasets/ManningsN"] | none | Grid file name and dataset path for the input Manning's n dataset | >=v3.5 |
| BOTTOM_FRICTION_COEF_DATASET | CHARACTER CHARACTER | [<grid file>] [<grid name>//"Datasets/BottomFricCoef"] | none | Grid file name and dataset path for the input bottom friction coefficient dataset | >=v4.0 |
| ROUGHNESS_HEIGHT_DATASET | CHARACTER CHARACTER | [<grid file>] [<grid name>//"Datasets/RoughnessHeight"] | none | Grid file name and dataset path for the input roughness height dataset | >=v4.0 |
Editing a Bottom Friction Dataset
Advanced Features
Table 2. Advanced Cards related to the bottom friction
| Card | Arguments | Default | Range | Description | CMS Versions |
|---|---|---|---|---|---|
| BED_SLOPE_FRICTION_FACTOR | character | OFF | ON| OFF | Specifies whether to include the bed slope friction factor or not in the calculation of the bed friction | >=4.0 |
| WAVE-CURRENT_MEAN_STRESS | character | W09 | W09 | DATA2 | DATA13 | F85 | HT95 | Defines the model used for calculating the mean bottom shear stress used in hydro | >=4.0 |
| MANNING_N_CONSTANT | real number | none | >=0.0 | Specifies a constant input Manning's n coefficient. Over-rides any previous bottom friction cards. | >=v4.0 |
| BOTTOM_FRICTION_COEF_CONSTANT | real number | none | >=0.0 | Specifies a constant input Bottom Friction Coefficient. Over-rides any previous bottom friction cards. | >=v4.0 |
| ROUGHNESS_HEIGHT_CONSTANT | real number | none | >=0.0 | Specifies a constant Roughness Height in m. Over-rides any previous bottom friction cards. | >=v4.0 |