CMS-Flow Model Parameters: Difference between revisions

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[[File:CMSFlow Model Parameters GeneralTab V13.2.12.png|thumb|right|500px|Figure 1. ''CMS-Flow Model Control'' : ''Model Parameters'' tab in SMS 13.2.12.]]
[[File:CMSFlow Model Parameters GeneralTab V13.2.12.png|thumb|right|500px|Figure 1. ''CMS-Flow Model Control'' : ''Model Parameters'' tab in SMS 13.2.12.]]
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.  
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.  
 
==General==
<br style="clear:both" />
===Time Control===
== General Parameters ==
The general parameters are the water density and temperature. The CMS-Flow cards for the general parameters are described in the table below.
 
'''Table 1. CMS-Flow cards related to the general parameters'''
{| border="1"
! Card  !! Arguments !! Default !!  Description
|-
|  WATER_DENSITY || REAL ||  1025 || Water density in kg/m^3.
|-
| WATER_TEMPERATURE || REAL  || 15 || Water temperature in degrees Celcius.
|}
 
== Time Control ==
Below are some of the  CMS cards related to the ''Time Control'' of the ''Flow'' tab. Table 1 provides a brief description of the CMS cards used for time control.
Below are some of the  CMS cards related to the ''Time Control'' of the ''Flow'' tab. Table 1 provides a brief description of the CMS cards used for time control.


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|-
|-
| DURATION_RAMP || REAL || 1.0 || Sets the length of the ramp period in which the model forcing is slowly ramped from zero.
| DURATION_RAMP || REAL || 1.0 || Sets the length of the ramp period in which the model forcing is slowly ramped from zero.
|}
===Hot Start===
The term Hot start refers to starting a  simulation with an initial condition other zero (cold start). Hot starts  are used for specifying initial conditions or restarting simulations at  intermediate times. The hot start controls are set in the ''Flow'' tab  of the ''CMS-Flow Model Control'' window.
Hot Start  File
[[Image:Hot_Start_HDFView.png|thumb|right|500px| Figure 1. HDFView showing the structure of the CMS Hot Start File. ]]
The  CMS hot start feature CMS lets the user restart simulations that have been stopped due to electric outages, hardware malfunctions, or model crashes. In the case of a model crash the user, may restart the model using larger solver iterations and/or time steps to stabilize the simulation. The user has the option to specify a hot start output time or an interval for outputting a recurring hot start file. Every time the hot start file is written, it overwrites the previous information. The CMS Hot Start file saves information on the water elevation (pressure), and current velocities. If the sediment transport is active, then the water depth and sediment concentrations are also saved for each size class. Only the very last record of information is preserved (no starting from earlier intervals).
The CMS hot start files are written as binary XMDF files by default. Depending on the type of hot start (single file or recurring), the names are as follows are saved in the directory of the CMS-Flow files:
* SingleHotStart.h5
* AutoHotStart.h5
After saving a CMS Hot Start file, it is a good idea to rename the file with a different name before using it as an initial conditions file. This way, the file will not be overwritten in future simulations.
'''Table 1.  Hot Start CMS-Flow Cards'''
{| class=wikitable border="1"
! Card !!  Arguments !! Default !! Range !!  Description
|-
| HOT_START_TIME || REAL || none || none || Single time after start at which to output a single hot start file.
|-
| AUTO_HOT_START_INTERVAL || REAL || none || none || Sets the recurring hot start output interval .
|}
*Initial conditions file
*Write Hot Start output file
*Automatic recurring Hot Start file
===Solution Scheme===
This refers to the temporal discretization of the hydrodynamic, sediment and salinity transport equations. There are two options in CMS:
1. Implicit - First order backward Euler scheme. Uses a time step on the order of 5-15 minutes. Appropriate for cases which can be simulated with large computational time steps such as long term morphology change at inlets.
2. Explicit - First order forward Euler scheme. Uses a time step on the order of 0.5-1.0 second. Appropriate for cases that vary quickly in time such as flooding or barrier island breaching.
*Matrix Solver*
{| class=wikitable border="1"
!  Card !! Arguments !! Default !! Range !!  Description
|-
| SOLUTION_SCHEME || CHARACTER || EXPLICIT || EXPLICIT <nowiki>|</nowiki> IMPLICIT || Determines the solution scheme used in CMS-Flow. 
|}
===Threats===
*Number of threads
<br style="clear:both" />
== Flow ==
== Sediment Transport ==
== Salinity/Temperature ==
The general parameters are the water density and temperature. The CMS-Flow cards for the general parameters are described in the table below.
'''Table 1. CMS-Flow cards related to the general parameters'''
{| border="1"
! Card  !! Arguments !! Default !!  Description
|-
|  WATER_DENSITY || REAL ||  1025 || Water density in kg/m^3.
|-
| WATER_TEMPERATURE || REAL  || 15 || Water temperature in degrees Celcius.
|}
|}


== Wave ==
== Wind ==
== Output ==
<br style="clear:both" />
<br style="clear:both" />


----
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[[CMS#Documentation Portal | Documentation Portal]]
[[CMS#Documentation Portal | Documentation Portal]]

Revision as of 19:17, 5 December 2022

Figure 1. CMS-Flow Model Control : Model Parameters tab in SMS 13.2.12.

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.

General

Time Control

Below are some of the CMS cards related to the Time Control of the Flow tab. Table 1 provides a brief description of the CMS cards used for time control.

Card Arguments Default Range Description
STARTING_JDATE REAL none none Julian data in YYDDD with YY being last two digits of the year, and DDD the Julian day of the year.
STARTING_JDATE_HOUR REAL none none Julian hour .
HYDRO_TIME_STEP REAL Calculated based on solution scheme and courant number none Sets to the time step for hydrodynamics in seconds.
DURATION_RUN REAL 48.0 >RAMP>0 Sets the duration of the model simulation in hours.
DURATION_RAMP REAL 1.0 Sets the length of the ramp period in which the model forcing is slowly ramped from zero.

Hot Start

The term Hot start refers to starting a simulation with an initial condition other zero (cold start). Hot starts are used for specifying initial conditions or restarting simulations at intermediate times. The hot start controls are set in the Flow tab of the CMS-Flow Model Control window.

Hot Start File

Figure 1. HDFView showing the structure of the CMS Hot Start File.

The CMS hot start feature CMS lets the user restart simulations that have been stopped due to electric outages, hardware malfunctions, or model crashes. In the case of a model crash the user, may restart the model using larger solver iterations and/or time steps to stabilize the simulation. The user has the option to specify a hot start output time or an interval for outputting a recurring hot start file. Every time the hot start file is written, it overwrites the previous information. The CMS Hot Start file saves information on the water elevation (pressure), and current velocities. If the sediment transport is active, then the water depth and sediment concentrations are also saved for each size class. Only the very last record of information is preserved (no starting from earlier intervals).

The CMS hot start files are written as binary XMDF files by default. Depending on the type of hot start (single file or recurring), the names are as follows are saved in the directory of the CMS-Flow files:

  • SingleHotStart.h5
  • AutoHotStart.h5

After saving a CMS Hot Start file, it is a good idea to rename the file with a different name before using it as an initial conditions file. This way, the file will not be overwritten in future simulations.

Table 1. Hot Start CMS-Flow Cards

Card Arguments Default Range Description
HOT_START_TIME REAL none none Single time after start at which to output a single hot start file.
AUTO_HOT_START_INTERVAL REAL none none Sets the recurring hot start output interval .
  • Initial conditions file
  • Write Hot Start output file
  • Automatic recurring Hot Start file

Solution Scheme

This refers to the temporal discretization of the hydrodynamic, sediment and salinity transport equations. There are two options in CMS: 1. Implicit - First order backward Euler scheme. Uses a time step on the order of 5-15 minutes. Appropriate for cases which can be simulated with large computational time steps such as long term morphology change at inlets. 2. Explicit - First order forward Euler scheme. Uses a time step on the order of 0.5-1.0 second. Appropriate for cases that vary quickly in time such as flooding or barrier island breaching.

  • Matrix Solver*
Card Arguments Default Range Description
SOLUTION_SCHEME CHARACTER EXPLICIT EXPLICIT | IMPLICIT Determines the solution scheme used in CMS-Flow.

Threats

  • Number of threads


Flow

Sediment Transport

Salinity/Temperature

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


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

Card Arguments Default Description
WATER_DENSITY REAL 1025 Water density in kg/m^3.
WATER_TEMPERATURE REAL 15 Water temperature in degrees Celcius.

Wave

Wind

Output


Documentation Portal

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