SMS:ADCIRC Boundary Conditions: Difference between revisions

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Much of ADCIRC's versatility as a model is due to the large number of different boundary types and boundary conditions available in the model. For detailed description of the ADCIRC boundary conditions, we refer you to the documentation provided by the ADCIRC development group at http://www.adcirc.org.
#redirect [[SMS:ADCIRC_Coverages#Boundary_Condition]]
 
== ADCIRC Boundary Types ==
Boundary types are assigned to feature arcs in the conceptual mode or nodestrings on the ADCIRC mesh. Correct boundary type assignments are very important to run a successful ADCIRC project. The following boundary types are available in SMS for ADCIRC:
* '''Unassigned''' – default, no boundary condition assigned
* '''Mainland''' –  This type of boundary represents a mainland boundary with no normal flow condition and free tangential slip.
* '''Island''' –  This type of boundary represents an island boundary with no normal flow condition and free tangential slip.  This can be selected for a closed feature arc.
* '''Normal Flow''' – This type of boundary represents a river inflow or open ocean boundary with a specified normal flow condition and free tangential slip. Discharges are specified either for harmonic discharge forcing or for time series discharge forcing.
* '''Normal Wave Radiation''' – This type of boundary represents an open boundary where waves are allowed to propagate freely out of the domain.
* '''Mainland Barrier''' – This type of boundary represents a mainland boundary comprised of a dike or levee. Non-zero normal flow is computed using a supercritical, free surface weir formula if the barrier is overtopped. Zero normal flow is assumed if the barrier is not overtopped.
* '''Island Barrier''' – This type of boundary represents a dike or levee that lies inside the computational domain.  Non-zero normal flow is compute using either subcritical or supercritical, free surface weir formula (based on the water level on both sides of the barrier) if the barrier is overtopped. Zero normal flow is assumed if the barrier is not overtopped. This boundary condition requires two nodestrings with an equal number of nodes.
* '''Weir''' – This type of boundary is similar to an Island Barrier with the addition of cross barrier flow.  Cross barrier flow simulates flow through the barrier simulating pipes or culverts  from one side to the other.  Flow rate and direction are based on barrier height, surface water elevation on both sides of the barrier, barrier coefficient and the appropriate barrier flow formula.  In addition cross barrier pipe flow rate and direction are based on pipe crown height, surface water elevation on both sides of the barrier, pipe friction coefficient, pipe diameter and the appropriate pipe flow formula.  This boundary condition requires two nodestrings with the same number of nodes.
* '''Zero Normal Velocity Gradient'''–  This type of boundary forces flow through the specified nodestring reflective of flow at a fictitious point inside the domain.  This is referred to as a weakly reflective boundary in some numerical engines. The fictitious point lies on the inward directed normal to the boundary a distance equal to the distance from the boundary node to its farthest 'neighbor. This should ensure that the fictitious point does not fall into an element that contains the boundary node.  The velocity at the fictitious point is determined by interpolation.
* '''Ocean''' –  This type of boundary represents an open interface for flow with a specified water surface elevation. Elevations are specified either as tidal constituents for harmonic forcing or as time series or water level.
 
=== ADCIRC Boundary Conditions Options ===
Depending upon the specified boundary type, the following boundary conditions are available:
 
{|class ="wikitable"
|+
!width="175"| Boundary Condition
!width="175"| Boundary Type
|- align="center"
| Essential w/<br>Tangential Slip || Mainland<br>Island<br>Normal Flow<br>Mainland Barrier
|- align="center"
| Essential w/o<br>Tangential Slip || Mainland<br>Island<br>Normal Flow<br>Mainland Barrier
|- align="center"
| Natural (w/<br>Tangential Slip) || Mainland<br>Island<br>Normal Flow<br>Mainland Barrier
|- align="center"
| [[SMS:ADCIRC Model Control#Tidal/Harmonics Tab|Tidal Constituents]] || Ocean
|- align="center"
| Curve || Ocean
|- align="center"
| Extract from Dataset|| Ocean
|}
 
== Nodal Boundary Conditions (Recording Stations) ==
The following boundary conditions can be assigned to an ADCIRC mesh node:
===2D Station Types===
* Elevation
* Velocity
* Concentration
* Meteorological
===3D Staion Types===
* Density/Temperature/Salinity
* Velocity
* Turbulence
===Description of Station===
Stations can be assigned a name to make station identification easier.
 
 
==Related Links==
* [[SMS:ADCIRC|ADCIRC]]
* [[SMS:ADCIRC Coverage|Coverage]]
* [[SMS:LTEA|Linear Truncation Error Analysis (LTEA)]]
* [[SMS:ADCIRC Mesh|Meshes]]
* [[SMS:ADCIRC Model Control|Model Control]]
* [[SMS:ADCIRC Spatial Attributes|Spatial Attributes]]
* [[SMS:Steering|Steering]]
 
 
{{Template:Navbox SMS}}
 
[[Category:ADCIRC|B]]

Latest revision as of 19:36, 20 November 2018