lmrThermalEquilibration.xml

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

    <!-- === Initial Geotherm Definition ========================================== -->
    <struct name="components" mergeType="merge">
        <struct name="tempProfile">
            <param name="Type">Ppc_Thermal_Profile</param>
            <param name="StartCoord" units="km">   0.0</param>
            <param name="EndCoord"   units="km"> -145.0</param>
            <param name="MinTemp" units="K"> 293.15 </param>
            <param name="MaxTemp" units="K"> 1573.15 </param>
            <param name="LinearCoefficient">0.00465139</param> 
            <param name="ExponentialCoefficient1">774.73 </param> 
            <param name="ExponentialCoefficient2">1.23996e-5</param>
            <param name="axis"> @VerticalAxis </param>
        </struct>
    </struct>
    <!-- The above function defines a geotherm via:
             temp = min_temp + LinearCoefficient * (start_coord - depth) + 
                    ExponentialCoefficient1 * (1 - exp(-ExponentialCoefficient2 * (start_coord - depth)))
         where any depth above StartCoord = MinTemp, and any depth below EndCoord = MaxTemp.
         
         By defining an approximately correct geotherm as an initial condition, the thermal equilibration
         time to steady-state can be reduced considerably.
    --> 
    <struct name="temperatureICs" mergeType="replace">
        <param name="type">CompositeVC</param>
        <list name="vcList">
            <struct>
                <param name="type"> AllNodesVC </param>
                <list name="variables">
                    <struct>
                        <param name="name"> temperature </param>
                        <param name="type"> func </param>
                        <param name="value"> tempProfile </param>
                    </struct>
                </list>
            </struct>
        </list>
    </struct>
    <!-- The geotherm is applied to the whole model domain in the above temperature Initial Condition -->
    <!-- === End of Initial Geotherm Definition =================================== -->
    
    
    
    
    
    <!-- === Optimisations for thermal equilibration phase ======================== -->

     <!-- By setting the air to be a fixed temperature, and changing it's thermal
          diffusivity, we can make the timestep 1 order of magnitude larger. -->
    <struct name="temperatureBCs" mergeType="merge">
        <list name="vcList" mergeType="merge">
            <struct>
                <param name="type"> MeshShapeVC </param>
                <param name="Shape"> airShape </param>
                <list name="variables">
                    <struct>
                        <param name="name">temperature</param>
                        <param name="type">double</param>
                        <param name="value" units="K">  293.15 </param>
                    </struct>
                </list>
            </struct>
        </list>
    </struct>
    <struct name="components" mergeType="merge">
        <struct name="air" mergeType="merge"> 
            <!-- Setting air diffusivity to be as small as rock will increase timestep length -->
            <param name="DiffusivityProperty" units="m*m/s" mergeType="replace"> 1e-6 </param>
        </struct>

        <!-- === Mesh parameters ========================== -->
        <struct name="linearMeshGenerator" mergeType="merge">
            <!-- Forces the mesh to be regular -->
            <param name="regular" mergeType="replace">True</param>            
        </struct>
        <!-- ============================================== -->
    
        <!-- Remove passive tracers, since they won't move 
             and slow the computation -->
        <struct name="passiveswarmOutputs" mergeType="replace">
            <param name="Type"> DummyComponent </param>
        </struct>
        <struct name="uppercrust_marker_PTSwarm" mergeType="replace">
            <param name="Type"> DummyComponent </param>
        </struct>
        <struct name="passiveTracerAdvect" mergeType="replace">
            <param name="Type"> DummyComponent </param>
        </struct>

        <struct name="stokesEqn" mergeType="merge">
            <param name="makeConvergenceFile" mergeType="replace"> false </param>
            <param name="killNonConvergent" mergeType="replace"> false </param>
        </struct>
    </struct>
    

    <list name="FieldVariablesToCheckpoint" mergeType="replace">
        <param>VelocityField</param>
        <param>PressureField</param>
        <param>TemperatureField</param>
        <param>TemperatureField-phiDotField</param>
    </list>
    
    <struct name="velocityBCs" mergeType="replace">
        <!-- Remove the Isostasy boundary condition from the
             base of the model -->
        <param name="type">CompositeVC</param>
        <list name="vcList">
            <struct>
                <param name="type">WallVC</param>
                <param name="wall">bottom</param>
                <list name="variables">
                    <struct>
                        <param name="name">vy</param>
                        <param name="type">double</param>
                        <param name="value" units="cm/yr">0.0</param>
                    </struct>
                </list>
            </struct>
        </list>
    </struct>
    
    <list name="plugins" mergeType="replace">
        <!-- Remove all plugins but a few important ones -->
        <struct>
            <param name="Type">StgFEM_SwarmVariableList</param>
            <param name="Context">context</param>
        </struct>
        <struct>
            <param name="Type">StgFEM_FeVariableList</param>
            <param name="Context">context</param>
        </struct>
        
        <struct>
            <param name="Type">Underworld_PureDiffusion</param>
            <param name="Context">context</param>
        </struct>
    </list>
    
    <param name="PureDiffusion_TimeSteps">200000000</param>
    
    <!-- === End of optimisations for thermal equilibration phase ================== -->
    


    
</StGermainData>