lmrVelocityBoundaries.xml

<?xml version="1.0" encoding="UTF-8"?>
<StGermainData xmlns="http://www.vpac.org/StGermain/XML_IO_Handler/Jun2003">

    <struct name="velocityBCs">
        <param name="type"> CompositeVC </param>
        <list name="vcList">
            <struct>
                <param name="type"> WallVC </param>
                <param name="wall"> left </param>
                <!-- This is where the boundary condition for the left wall
                     is defined. The unit is negative, because the x axis
                     goes negative to positive, left to right -->
                <list name="variables">
                    <struct>
                        <param name="name"> vx </param>
                        <param name="type"> double </param>
                        <param name="value" units="cm/yr"> -1.0 </param>
                    </struct>
                </list>
            </struct>

            <struct>
                <param name="type"> WallVC </param>
                <param name="wall"> right </param>
                <list name="variables">
                    <struct>
                        <param name="name"> vx </param>
                        <param name="type"> double </param>
                        <param name="value" units="cm/yr"> 1.0 </param>
                    </struct>
                </list>
            </struct>
            
            <!-- NOTE: The 'front' and 'back' walls are only activated when in 
                  3D. The definitions below are for free-slip, no outflow. -->
            <struct>
                <param name="type"> WallVC </param>
                <param name="wall"> front </param>
                <list name="variables">
                    <struct>
                        <param name="name"> vz </param>
                        <param name="type"> double </param>
                        <param name="value" units="cm/yr"> 0.0 </param>
                    </struct>
                </list>
            </struct>
            
            <struct>
                <param name="type"> WallVC </param>
                <param name="wall"> back </param>
                <list name="variables">
                    <struct>
                        <param name="name"> vz </param>
                        <param name="type"> double </param>
                        <param name="value" units="cm/yr"> 0.0 </param>
                    </struct>
                </list>
            </struct>

            <struct>
                <param name="type"> WallVC </param>
                <param name="wall"> bottom </param>
                <!-- The isostatic boundary condition applied to the bottom of
                     the model is controlled by a function. See the bottom of 
                     this file for some controls -->
                <list name="variables">
                    <struct>
                        <param name="name"> vy </param>
                        <param name="type"> func </param>
                        <param name="value"> lecode_tools_Isostasy </param>
                    </struct>
                </list>
            </struct>
        </list>
    </struct>
    
    
    <!-- === Example Ppc function for wallVC ============= -->
    <!-- The following structs define a time dependent wall VC, where between
         t=0 and t=1myr, the wall velocity increases from 0.2 to -2.0 cm/yr. 
         Note that the speed increase is linearly interpolated between one
         case to the next (hence the 'l' for linear in the "Interpolate"
         param).
         
         To use this function, change the left wallVC "type" to be "func", and 
         set the "value" to be "left-wall-VC" (and get rid of any units). -->
         
    <struct name="components" mergeType="merge">
        <struct name="current_time" mergeType="replace">
            <param name="Type"> Ppc_Current_Time </param>
        </struct>
        
        <struct name="left-wall-VC">
            <param name="Type"> Ppc_Switch </param>
            <param name="Field"> current_time </param>
            <param name="Interpolate"> l </param>
            <list name="CaseList">
                <struct>
                    <param name="Case" units="Myr"> 0 </param>
                    <param name="Value" units="cm/yr"> -0.2 </param>
                </struct>
                <struct>
                    <param name="Case" units="Myr"> 1 </param>
                    <param name="Value" units="cm/yr"> -2.0 </param>
                </struct>
            </list>
        </struct>

        <!-- Another example boundary condition, where instead of changing through
             time, the velocity depends on depth.
             In this case, from y = -160 km depth to y = -115 km, the extension 
             velocity is 5 cm/yr. From y = -115 km to the top of the model (y = 15 km)
             the velocity is 1 cm/yr.
             This can be used to simulate a plate moving over the asthenosphere, for
             example.
             Velocities between depths are linearly interpolated.
             To use this function, change the left wallVC "type" to be "func", and 
             set the "value" to be "vertical_left-wall-VC" (and get rid of any units).
        -->
        <struct name="vertical_left-wall-VC">
            <param name="Type"> Ppc_Switch </param>
            <param name="Field"> elevation </param>
            <param name="Interpolate"> l </param>
            <list name="CaseList">
                <struct>
                    <param name="Case" units="km"> -160.0 </param>
                    <param name="Value" units="cm/yr"> -5.0 </param>
                </struct>
                <struct>
                    <param name="Case" units="km"> -115.0 </param>
                    <param name="Value" units="cm/yr"> -5.0 </param>
                </struct>
                <struct>
                    <param name="Case" units="km"> -115.0 </param>
                    <param name="Value" units="cm/yr"> -1.0 </param>
                </struct>
                <struct>
                    <param name="Case" units="km"> 15.0 </param>
                    <param name="Value" units="cm/yr"> -1.0 </param>
                </struct>
            </list>
        </struct>
        
    </struct>
    
    
    
    
    <!--=== Moving mesh ==================================== -->
    <!-- This section of XML controls whether the model domain moves with the
         boundary conditions applied. By default this is turned off, and so you
         will notice that the material pulled out of the models will flow through
         the fixed walls.
         If it is turned on (by uncommenting the following code), then the left 
         and right walls will move with the material, stretching the model over
         time.
         
         Using a moving mesh is has some advantages, e.g. no material is lost out
         the sides of the model. However, given enough extension, the mesh 
         eventually looses it's ideal square shape, and can lead to errors. 
         Additionally, the size of shear zones (faults) is dependent on mesh 
         resolution, so as the mesh changes, fault patterns may also change in 
         behavior. 
         Therefore, the mesh deformation is turned off by default.
         To turn it back on, simply uncomment the code below this documentation.

         === Commonly modified sections ===
         The "static<wall>" params tell Underworld whether the wall will remain
         fixed (as a flux boundary condition), or whether the wall will move with
         the kinematic boundary conditions.

         "wrapTop" will give the model a free-surface BC on the top wall. If this
         is on, then the linearMeshGenerator (in lmrNumerics.xml) needs to have
         "regular" set to False.
    -->

    <!--    
    <include>Underworld/ArtDisplacementField.xml</include>

    <struct name="EulerDeform">
        <list name="systems">
            <struct>
                <param name="staticTop">    True  </param>
                <param name="staticBottom"> True  </param>
                
                <param name="staticLeft">   False </param>
                <param name="staticRight">  False </param>
                
                <param name="staticFront">  True  </param>
                <param name="staticBack">   True  </param>
                
                <param name="wrapTop"> False </param>
                
                <param name="mesh"> velocityMesh </param>
                <param name="remesher"> velocityRemesher </param>
                <param name="velocityField"> VelocityField </param>
                <list name="fields">
                    <struct>
                        <param name="field"> VelocityField </param>
                        <param name="variable"> velocity </param>
                    </struct>
                </list>
            </struct>
        </list>
    </struct>
    <struct name="components" mergeType="merge">
        <struct name="velocityRemesher">
            <param name="Type"> RegularRemesherCmpt </param>
            <param name="mesh"> velocityMesh </param>
            <list name="remeshDims">
                <param> 0 </param>
                <param> 1 </param>
                <param> 2 </param>
            </list>
        </struct>
    </struct>
    
    <list name="plugins" mergeType="merge">
        <struct>
            <param name="Type"> Underworld_EulerDeform </param>
            <param name="Context"> context </param>
        </struct>
	    <struct>
            <param name="Type"> Underworld_MeshAdvectionCorrection </param>
            <param name="Context"> context </param>
        </struct>
    </list>
    
    <param name="MeshAdvectionCorrection_UseArtDisplacementField"> True </param>
    -->
    <!--=== End of Moving Mesh ============================== -->
    
    
    
    
    
    <!--=== Isostasy functionality ========================== -->
    <list name="plugins" mergeType="merge">
        <struct>
            <!-- === Commonly modified ================== -->
            <param name="rhoZeroMaterial">mantle</param>
            <param name="UseAverage">False</param>
            <!-- ======================================== -->
            <param name="Type"> lecode_tools_Isostasy </param>
            <param name="Context">context</param>
            <param name="mesh">linearMesh</param>
            <param name="VerticalAxis">@VerticalAxis</param>
            <param name="SurfaceIndex">@elementResJ</param>
            <param name="swarm">picIntegrationPoints</param>
            <param name="velocityField">VelocityField</param>
            <param name="sle">stokesEqn</param>
            <param name="Manager">default_ppcManager</param>
            <param name="DensityLabel">DensityProperty</param>
            <param name="MaxIterations">-1</param>
        </struct>
    </list>
    <!--===================================================== -->
    
</StGermainData>