CMS-Flow Bottom Friction: Difference between revisions

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== Bottom Friction Dataset ==
== Creating Bottom Friction Dataset ==
=== Creating ===
[[image:CMS-Flow_Model_Control-Input-Default.png|thumb|left|500px|Figure  2.4. Initialization of the ''Bottom Friction Dataset'' in SMS 11.0]]
[[image:CMS-Flow_Model_Control-Input-Default.png|thumb|left|500px|Figure  2.4. Initialization of the ''Bottom Friction Dataset'' in SMS 11.0]]
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.  
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.  
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[[image:CMS-Flow_Project_Explorer_Bottom_Friction.png|thumb|left|600px|Figure  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  3. Three SMS Project Explorer showing the Manning's n, Bottom  Friction Coefficient and Roughness Height datasets.]]
Once the ''Bottom Friction Dataset'' is created and the ''CMS-Flow Model Control'' window closed, a new auxiliary dataset will appear in the ''SMS Project Explorer'' (see Figure 3).  
Once the ''Bottom Friction Dataset'' is created and the ''CMS-Flow Model Control'' window closed, a new auxiliary dataset will appear in the ''SMS Project Explorer'' (see Figure 3). Table 1. shows a list of the CMS cards related to the bottom friction datasets.  


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=== Editing ===
'''Table 1. SMS Cards related to the bottom friction datasets'''
{| border="1"
! Card !! Arguments !! Default !!  Range !! Description !! Versions
|-
|  USE_WALL_FRICTION || CHARACTER || ON || ON  <nowiki>|</nowiki> 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
|}


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== Editing the Bottom Friction Dataset==
[[Image:Shark_Fig18.PNG|thumb|right|500px||Figure 4. Manning n contours after modifying the areas under all three bridges.]]
[[Image:Shark_Fig18.PNG|thumb|right|500px||Figure 4. Manning n contours after modifying the areas under all three bridges.]]
Bottom roughness datasets may be edited manually, using the ''Data Calculator'' or by interpolating from a scatter set. Figure 4 shows an example where the Manning's n coefficient is increased for Shark River Inlet to account for the presence of vertical piles.  
Bottom roughness datasets may be edited manually, using the ''Data Calculator'' or by interpolating from a scatter set. Figure 4 shows an example where the Manning's n coefficient is increased for Shark River Inlet to account for the presence of vertical piles.  
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To interpolate bottom roughness data from a scatter set
To interpolate bottom roughness data from a scatter set


=== Exporting ===
== Exporting the Bottom Friction Dataset ==
[[Image:Export_BottomFrictCoef.png|thumb|right|500px||Figure 4. Manning n contours  after modifying the areas under all three bridges.]]
 
Exporting the bottom roughness (friction) datasets is useful for creating different project alternatives or when switching from different bottom roughness datasets types such as from ''Manning's n'' to ''Bottom Friction Coefficient'' and back.  
Exporting the bottom roughness (friction) datasets is useful for creating different project alternatives or when switching from different bottom roughness datasets types such as from ''Manning's n'' to ''Bottom Friction Coefficient'' and back.  


 
[[Image:Export_Data_Set.png|thumb|right|400px||Figure 4. Manning n  contours  after modifying the areas under all three bridges.]]


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'''Table 1. SMS Cards related to the bottom friction'''
{| border="1"
! Card !! Arguments !! Default !! Range !! Description !! Versions
|-
| USE_WALL_FRICTION || CHARACTER || ON || ON <nowiki>|</nowiki> 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 ==
== Editing a Bottom Friction Dataset ==


Revision as of 19:10, 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.

Figure 1. Specification of Manning's n coefficient in the Cells tab of the CMS-Flow Model Control window in SMS 10.1
Figure 2 Specification of the Bottom Friction Dataset the Input tab of the CMS-Flow Model Control window in SMS 11.0


Creating Bottom Friction Dataset

Figure 2.4. Initialization of the Bottom Friction Dataset in SMS 11.0

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.


Figure 3. Three SMS Project Explorer showing the Manning's n, Bottom Friction Coefficient and Roughness Height datasets.

Once the Bottom Friction Dataset is created and the CMS-Flow Model Control window closed, a new auxiliary dataset will appear in the SMS Project Explorer (see Figure 3). Table 1. shows a list of the CMS cards related to the bottom friction datasets.


Table 1. SMS Cards related to the bottom friction datasets

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 the Bottom Friction Dataset

Figure 4. Manning n contours after modifying the areas under all three bridges.

Bottom roughness datasets may be edited manually, using the Data Calculator or by interpolating from a scatter set. Figure 4 shows an example where the Manning's n coefficient is increased for Shark River Inlet to account for the presence of vertical piles.

To interpolate bottom roughness data from a scatter set

Exporting the Bottom Friction Dataset

Figure 4. Manning n contours after modifying the areas under all three bridges.

Exporting the bottom roughness (friction) datasets is useful for creating different project alternatives or when switching from different bottom roughness datasets types such as from Manning's n to Bottom Friction Coefficient and back.

Figure 4. Manning n contours after modifying the areas under all three bridges.


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

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