lmrNumerics.xml

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

    <param name="gravity" units="m*s^-2"> 9.81 </param>

    <!-- === Basic numerical controls ========================= -->
    <param name="particlesPerCell"> 40 </param>
    <param name="courantFactor"> 0.5 </param>
    <!-- ====================================================== -->

    <!-- === Timestep controls ================================ -->
        <!-- timestepFactor = scales the timestep (best not to go >1). If your model "wobbles" or
                              has flickering in strain-rate or viscosity, try reducing this value.
             maxTimeStepSize = if the dt is > than this, cut it back.
             DtGranularity = cut the dt back to the nearest factor of this
                             WARNING! Using a high DtGranularity can result in timesteps of 0!
                             If this happens, try reducing or removing this number -->
    <param name="timestepFactor"> 0.5 </param>
    <param name="maxTimeStepSize" units="yr"> 1e7 </param>
    <!--param name="DtGranularity" units="yr"> 1000 </param-->
    <!-- ===<=================================================== -->



    <!-- === Output controls ================================== -->
    <list name="FieldVariablesToCheckpoint" mergeType="merge">
        <!-- === Must be checkpointed for model restart ===== -->
        <param> VelocityField </param>
        <param> PressureField </param>
        <param> TemperatureField </param>
        <param> TemperatureField-phiDotField </param>
        <param> StrainRateField </param>
        <param> StressField </param>
        <!-- ================================================ -->

        <param> StrainRateInvariantField </param>
        <param> StressInvariantField </param>

        <param> isBrittle </param>
        <param> BrittleTotalStrainField </param>
        <param> BrittleStrainRateField </param>
        <param> ViscosityField </param>
        <param> MaterialIndexField </param>
    </list>

    <!-- ====================================================== -->





    <struct name="components" mergeType="merge">
    <!-- === Defining fundamental forces ========================================== -->

        <!-- ====== Buoyancy forces ============================== -->
        <struct name="buoyancyFunc">
            <!-- buoyancyFunc calculates the force (F = ma) of all the materials in the model domain.
                 Every particle will be processed as such, using it's value for DensityProperty. -->
            <param name="Type">Ppc_a_Vector</param>
            <param name="Alpha">DensityProperty</param>
            <param name="vi">0</param>
            <param name="vj" units="m*s^-2">-9.81</param>
            <param name="vk">0</param>
        </struct>

        <struct name="buoyancyForceTerm" mergeType="replace">
            <!-- Hook in our defined buoyancyFunc into the fundamental UW equations,
                 with buoyancy being defined as a body force (mom_force). -->
            <param name="Type">VectorAssemblyTerm_NA__F</param>
            <param name="ForceVector">mom_force</param>
            <param name="functionLabel">buoyancyFunc</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="Manager">default_ppcManager</param>
        </struct>
        <!-- ====== End of Buoyancy forces ======================= -->


        <!-- ====== Thermal Energy =============================== -->
        <struct name="sourceTerms_thermalEqn">
            <param name="Type">Ppc_Operation</param>
            <param name="Operation"> + </param>
            <list name="Properties">
                <!-- Add or remove sources of thermal energy via this operation.
                     NOTE: having just a single term is OK. -->
                <param> radiogenicHeating </param>
            </list>
        </struct>

        <!-- radiogenicHeating = radiogenic_heat_production / (heat_capacity * density ) -->
        <struct name="radiogenicHeating">
            <param name="Type">Ppc_Operation</param>
            <param name="Operation"> / </param>
            <list name="Properties">
                <param>RadiogenicHeatProductionProperty</param>
                <param>rho_cp</param>
            </list>
        </struct>
        <struct name="rho_cp">
            <param name="Type">Ppc_Operation</param>
            <param name="Operation"> * </param>
            <list name="Properties">
                <param>DensityProperty</param>
                <param>CpProperty</param>
            </list>
        </struct>

        <struct name="thermalEqn">
            <!-- This struct allows additional energy sources into the system, for
                 example: radiogenic heating, or some other user computed function, etc.
                 The sources of energy are incorporated via the sourceTerms_thermalEqn
                 struct defined above.-->
            <param name="Type">VectorAssemblyTerm_NA__F</param>
            <param name="ForceVector">residual</param>
            <param name="functionLabel">sourceTerms_thermalEqn</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="Manager">default_ppcManager</param>
        </struct>

        <!-- === Following structs disabled until further testing! === -->
        <!--struct name="viscousHeating">
            <param name="Type"> ViscousHeatingTermPpc </param>
            <param name="ForceVector">residual</param>
            <param name="EnergyEqn">EnergyEqn</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="DeviatoricStressField"> StressField </param>
            <param name="StrainRateField"> StrainRateField </param>
            <param name="DensityLabel"> DensityProperty </param>
            <param name="CpLabel"> CpProperty </param>
        </struct-->

        <struct name="adiabaticHeating">
            <param name="Type"> AdiabaticHeatingTermPpc </param>
            <param name="ForceVector"> residual </param>
            <param name="EnergyEqn"> EnergyEqn </param>
            <param name="Swarm"> picIntegrationPoints </param>
            <param name="VelocityField"> VelocityField </param>
            <param name="TemperatureField"> TemperatureField </param>
            <param name="CpLabel"> CpProperty </param>
            <param name="ThermalExpansivityLabel"> ThermalExpansivityProperty </param>
        </struct>

        <struct name="defaultResidualForceTerm" mergeType="replace">
            <!-- This struct ensures advection/diffusion is solved. -->
            <param name="Type">SUPGAdvDiffTermPpc</param>
            <param name="ForceVector">residual</param>
            <param name="EnergyEqn">EnergyEqn</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="VelocityField">VelocityField</param>
            <param name="PhiField">TemperatureField</param>
            <param name="DiffusivityLabel">DiffusivityProperty</param>
        </struct>
        <!-- ====== End of Thermal Energy ======================== -->

    <!-- === End of fundamental forces definitions ========================================== -->














    <!-- === The nitty-gritty numerics (best to leave alone if unsure) ====================== -->

        <!-- The Ppc Manager-->
        <struct name="default_ppcManager">
            <param name="Type">PpcManager</param>
            <param name="MaterialSwarm"> materialSwarm </param>
            <param name="IntegrationSwarm"> picIntegrationPoints </param>
            <param name="Scaling">default_scaling</param>
            <param name="Mesh"> linearMesh </param>
            <param name="Gravity"> gravity </param>

            <!-- The "Properties" list defines what MaterialExtensions the model has.
                 Each property must have a name, and every material defined must reference it.
                 MaterialExtensions also have a number of optional storage and calculation options:
                    <param name="StoreOnMesh"> True </param>            Store the result on the mesh.
                    <param name="StoreOnParticles"> True </param>       Store the result on the particles.
                    <param name="StoreNLOnParticles"> True </param>     Re-calculate this property on every non-linear iteration.
                    <param name="StorePreviousValue"> True </param>     Store the previous timestep's value on the particles.
                    <param name="PassiveProperty"> True </param>        Force the calculation of this property (Required if the property is not part of the stokes-flow/energy equations).
                 NOTE: If you have any dependence in your variables on parameters that need to be calculated, e.g., pressure, ensure
                       you enable StoreNLOnParticle - this means the calculation will use the 'best' result of the non-linear solver.
            -->
            <list name="Properties">
                <struct>
                    <param name="PropertyName"> DensityProperty </param>
                    <param name="StoreOnParticles"> True </param>
                    <param name="StoreOnMesh"> True </param>
                    <param name="StoreNLOnParticles"> True </param>
                </struct>

                <!-- === Thermal properties ============== -->
                <struct>
                    <param name="PropertyName"> DiffusivityProperty </param>
                </struct>
                <struct>
                    <param name="PropertyName"> CpProperty </param>
                </struct>
                <struct>
                    <param name="PropertyName"> ThermalExpansivityProperty </param>
                </struct>
                <struct>
                    <param name="PropertyName"> RadiogenicHeatProductionProperty </param>
                </struct>
                <!-- ===================================== -->
            </list>
        </struct>

        <!-- === Need these Ppc_Constants if you DON'T use melt ============== -->
        <struct name="MeltFractionProperty">
            <param name="Type"> Ppc_Constant </param>
            <param name="Value"> 0 </param>
        </struct>
        <struct name="MeltFractionLimitProperty">
            <param name="Type"> Ppc_Constant </param>
            <param name="Value"> 0 </param>
        </struct>
        <struct name="MeltExpansionProperty">
            <param name="Type"> Ppc_Constant </param>
            <param name="Value"> 0 </param>
        </struct>
        <struct name="LiquidusProperty">
            <param name="Type"> Ppc_Constant </param>
            <param name="Value"> 0 </param>
        </struct>
        <struct name="SolidusProperty">
            <param name="Type"> Ppc_Constant </param>
            <param name="Value"> 0 </param>
        </struct>
        <struct name="LatentHeatFusionProperty">
            <param name="Type"> Ppc_Constant </param>
            <param name="Value"> 0 </param>
        </struct>
        <!-- ===================================== -->

        <!-- Allow PPC to access variables -->
        <struct name="temperature_ppc_wrapper">
            <param name="Type">Ppc_Variable</param>
            <param name="FieldVariable">TemperatureField</param>
        </struct>
        <struct name="pressure_ppc_wrapper">
            <param name="Type">Ppc_Variable</param>
            <param name="FieldVariable">PressureField</param>
        </struct>


        <!-- === User-defined fields ============================= -->
            <!-- Swarm variables are interpolated to the mesh
                 using SwarmVariableField -->
        <struct name="isBrittle">
            <param name="Type">SwarmVariableField</param>
            <param name="swarmVariable">materialSwarm-HasYielded</param>
            <param name="Mesh">linearMesh</param>
            <param name="MaterialSwarm">materialSwarm</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="Context">context</param>
        </struct>
        <struct name="BrittleTotalStrainField">
            <param name="Type">SwarmVariableField</param>
            <param name="swarmVariable">materialSwarm-PostFailureWeakening</param>
            <param name="Mesh">linearMesh</param>
            <param name="MaterialSwarm">materialSwarm</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="Context">context</param>
        </struct>
        <struct name="BrittleStrainRateField">
            <param name="Type">SwarmVariableField</param>
            <param name="swarmVariable">materialSwarm-PostFailureWeakeningIncrement</param>
            <param name="Mesh">linearMesh</param>
            <param name="MaterialSwarm">materialSwarm</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="Context">context</param>
        </struct>
        <!-- Disabled due to bugs -->
        <!--
        <struct name="cumulativeTotalStrainField">
            <param name="Type">SwarmVariableField</param>
            <param name="swarmVariable">materialSwarm-cumulativeTotalStrain</param>
            <param name="Mesh">linearMesh</param>
            <param name="MaterialSwarm">materialSwarm</param>
            <param name="Swarm">picIntegrationPoints</param>
            <param name="Context">context</param>
        </struct>
        -->
        <!-- ====================================================== -->


        <!-- === Scaling options ============================= -->
            <!-- If any of these coefficients are not equal to 1.0, then you must
                 ensure all your values have units assigned.-->
        <struct name="default_scaling">
            <param name="Type">Scaling</param>
            <param name="spaceCoefficient_meters">1.0</param>
            <param name="timeCoefficient_seconds">1.0</param>
            <param name="massCoefficient_kilograms">1.0</param>
            <param name="temperatureCoefficient_kelvin">1.0</param>
            <param name="electricCurrentCoefficient_amperes">1</param>
        </struct>
        <!-- ================================================ -->


        <!-- === Solver details ============================= -->
        <struct name="weights" mergeType="replace">
            <!-- === Most modified ============== -->
            <param name="maxDeletions"> 0 </param>
            <param name="maxSplits"> 100 </param>
            <param name="Inflow"> True </param>
            <!-- ================================ -->
            <param name="Type"> PCDVC </param>
            <param name="resolutionX"> 10 </param>
            <param name="resolutionY"> 10 </param>
            <param name="resolutionZ"> 10 </param>
            <param name="lowerT"> 0.6 </param>
            <param name="upperT"> 5 </param>
            <param name="Threshold"> 0.95 </param>
            <param name="CentPosRatio"> 0.01 </param>
            <param name="MaterialPointsSwarm"> materialSwarm </param>
            <param name="splitInInterfaceCells"> False </param>
            <!--param name="allowSplittingInBoundaryInterfaceCells"> False </param-->
        </struct>

        <struct name="uzawa" mergeType="merge">
            <param name="monitor" mergeType="replace">True</param>
            <param name="tolerance" mergeType="replace">@linearTolerance</param>
            <param name="maxIterations" mergeType="replace">@linearMaxIterations</param>
            <param name="minIterations" mergeType="replace">@linearMinIterations</param>
        </struct>

        <struct name="stokesEqn" mergeType="merge">
            <param name="nonLinearMinIterations" mergeType="replace">@nonLinearMinIterations</param>
            <param name="makeConvergenceFile" mergeType="replace"> true </param>
            <param name="killNonConvergent" mergeType="replace"> true </param>
        </struct>

        <!-- ============================================== -->


        <!-- === Implementation for flux BCs =============== -->
        <struct name="borderCellLayout">
            <param name="Type">SingleCellLayout</param>
        </struct>
        <struct name="borderParticleLayout">
            <param name="Type">GaussBorderParticleLayout</param>
        </struct>
        <struct name="borderGaussSwarm">
            <param name="Type">IntegrationPointsSwarm</param>
            <param name="CellLayout">borderCellLayout</param>
            <param name="ParticleLayout">borderParticleLayout</param>
            <param name="FeMesh">elementMesh</param>
            <param name="TimeIntegrator">timeIntegrator</param>
            <param name="IntegrationPointMapper">borderGaussMapper</param>
        </struct>
        <struct name="borderGaussMapper">
            <param name="Type">GaussMapper</param>
            <param name="IntegrationPointsSwarm">borderGaussSwarm</param>
            <param name="MaterialPointsSwarm">borderGaussMaterialSwarm</param>
        </struct>
        <struct name="borderBackgroundLayout">
            <param name="Type">BackgroundParticleLayout</param>
        </struct>
        <struct name="borderGaussMSwarmMovementHandler">
            <param name="Type">ParticleMovementHandler</param>
        </struct>
        <struct name="borderGaussMaterialSwarm">
            <param name="Type">MaterialPointsSwarm</param>
            <param name="CellLayout">borderCellLayout</param>
            <param name="ParticleLayout">borderBackgroundLayout</param>
            <param name="FeMesh">elementMesh</param>
            <list name="ParticleCommHandlers">
                <param>borderGaussMSwarmMovementHandler</param>
            </list>
        </struct>
        <!-- ============================================== -->

        <!-- === Mesh parameters ========================== -->
        <struct name="linearMeshGenerator" mergeType="merge">
            <!-- Forces the mesh to be regular -->
            <param name="regular" mergeType="replace">True</param>
        </struct>
        <!-- ============================================== -->

	<!-- === Use multiple thermal timestpes if needed = -->
	<struct name="EnergyEqn" mergeType="merge">
		<param name="multiThermalSteps"> True </param>
	</struct>
        <!-- ============================================== -->

    </struct>

    <list name="plugins" mergeType="merge">
        <struct>
            <!-- The pressure calibration plugin is used to ensure
                 Underworld uses real-world pressure values (appr-
                 oximately). Stokes flow only has a pressure grad-
                 iant term, so the calibration plugin is used to
                 ensure that the pressure at the surface is appro-
                 ximately 0 Pa. This is important for rheologies 
                 that rely on the lithostatic pressure (e.g., 
                 Drucker-Prager brittle faulting).
                 The plugin calculates the average pressure across
                 the top of the model, and removes that value from
                 everywhere in the model. -->
            <param name="Type"> Underworld_PressureCalibration </param>
            <param name="Context"> context </param>
            <param name="UsingTopPressure"> True </param>
            <param name="ReferenceHeight"> maxY </param>
        </struct>

        <!-- The following plugins write a text file into the results
             folder, which lists all the swarm and field variables
             respectively available for outputting -->
        <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"> StgFEM_PeakMemory </param>
            <param name="Context"> context </param>
        </struct>
    </list>

    <!-- === Numerical controls (that probably shouldn't be touched) ==== -->
    <param name="shadowDepth"> 1 </param>
    <param name="allowUnbalancing"> True </param>
    <param name="timeIntegratorOrder"> 2 </param>
    <!-- ================================================================ -->

    <!-- === Mesh parameters ======================= -->
    <param name="VerticalAxis"> 1 </param>
    <!-- =========================================== -->





    <!-- NOTE: All of the following values are ALWAYS overwritten by lmrRunModel.py
               They have been relegated to the bottom of this file because they are
               should never have to be directly modified by any user. -->
    <!-- === Mesh parameters ======================= -->
    <!-- These values are always overwritten -->
    <param name="dim"> 2 </param>
    <param name="elementResI"> 208 </param>
    <param name="elementResJ"> 112 </param>
    <param name="elementResK"> 0 </param>
    <!-- =========================================== -->

    <!-- === Numerical tolerance values ============ -->
    <!-- These values are always overwritten -->
    <param name="linearTolerance"> 1e-5 </param>
    <param name="linearMinIterations"> 10 </param>
    <param name="linearMaxIterations"> 15000 </param>

    <param name="nonLinearTolerance"> 1e-3 </param>
    <param name="nonLinearMinIterations"> 10 </param>
    <param name="nonLinearMaxIterations"> 500 </param>
    <!-- =========================================== -->


    <!-- === Output controls ====================== -->
    <!-- These values are always overwritten -->
    <param name="outputPath"> ./model </param>
    <param name="checkpointEvery"> 1000000000 </param>
    <param name="dumpEvery">       1000000000 </param>
    <param name="checkpointAtTimeInc" units="yr"> 1e10 </param>

    <!-- === Model timing  ======================== -->
    <!-- These values are always overwritten -->
    <param name="maxTimeSteps"> 2000000 </param>
    <param name="end" units="yr"> 1e12 </param>
    <!-- =========================================== -->


</StGermainData>