findThermalIC

Find thermal initial conditions assigned to a geometric region

Syntax

tica = findThermalIC(thermalmodel.InitialConditions,RegionType,RegionID)

Description

tica = findThermalIC(thermalmodel.InitialConditions,RegionType,RegionID) returns the thermal initial condition assigned to the specified region.

Examples

Find Initial Temperatures for Faces of 2-D Geometry

Create a transient thermal model that has three faces.

thermalmodel = createpde("thermal","transient");
geometryFromEdges(thermalmodel,@lshapeg);
pdegplot(thermalmodel,"FaceLabels","on")
ylim([-1.1 1.1])
axis equal

Set initial temperatures for each face.

thermalIC(thermalmodel,10,"Face",1);
thermalIC(thermalmodel,20,"Face",2);
thermalIC(thermalmodel,30,"Face",3);

Check the initial condition specification for face 1.

ticaFace1 = findThermalIC(thermalmodel.InitialConditions,"Face",1)

ticaFace1 = 
  GeometricThermalICs with properties:

            RegionType: 'face'
              RegionID: 1
    InitialTemperature: 10

Check the initial temperature specifications for faces 2 and 3.

tica = findThermalIC(thermalmodel.InitialConditions,"Face",[2 3]);
ticaFace2 = tica(1)

ticaFace2 = 
  GeometricThermalICs with properties:

            RegionType: 'face'
              RegionID: 2
    InitialTemperature: 20

ticaFace3 = tica(2)

ticaFace3 = 
  GeometricThermalICs with properties:

            RegionType: 'face'
              RegionID: 3
    InitialTemperature: 30

Find Initial Temperatures for Cells of 3-D Geometry

Create a geometry that consists of three nested cylinders and include the geometry in a transient thermal model.

gm = multicylinder([5 10 15],2)

gm = 
  DiscreteGeometry with properties:

       NumCells: 3
       NumFaces: 9
       NumEdges: 6
    NumVertices: 6
       Vertices: [6x3 double]

thermalmodel = createpde("thermal","transient");
thermalmodel.Geometry = gm;
pdegplot(thermalmodel,"CellLabels","on","FaceAlpha",0.5)

Set initial temperatures for each cell.

thermalIC(thermalmodel,0,"Cell",1);
thermalIC(thermalmodel,100,"Cell",2);
thermalIC(thermalmodel,0,"Cell",3);

Check the initial condition specification for cell 1.

ticaCell1 = findThermalIC(thermalmodel.InitialConditions,"Cell",1)

ticaCell1 = 
  GeometricThermalICs with properties:

            RegionType: 'cell'
              RegionID: 1
    InitialTemperature: 0

Check the initial condition specification for cells 2 and 3.

tica = findThermalIC(thermalmodel.InitialConditions,"Cell",[2:3]);
ticaCell2 = tica(1)

ticaCell2 = 
  GeometricThermalICs with properties:

            RegionType: 'cell'
              RegionID: 2
    InitialTemperature: 100

ticaCell3 = tica(2)

ticaCell3 = 
  GeometricThermalICs with properties:

            RegionType: 'cell'
              RegionID: 3
    InitialTemperature: 0

Find Initial Temperature Set by Using Previously Obtained Solution

Create a thermal model and include a square geometry.

thermalmodel = createpde("thermal","transient");
gm = @squareg;
geometryFromEdges(thermalmodel,gm);
pdegplot(thermalmodel,"FaceLabels","on")
ylim([-1.1 1.1])
axis equal

Specify material properties, heat source, set initial and boundary conditions.

thermalProperties(thermalmodel,"ThermalConductivity",500,...
                               "MassDensity",200,...
                               "SpecificHeat",100);
internalHeatSource(thermalmodel,2);                            
thermalBC(thermalmodel,"Edge",[1 3],"Temperature",100);
thermalIC(thermalmodel,0);

Generate a mesh and solve the problem.

generateMesh(thermalmodel);
tlist = 0:0.5:10;
result1 = solve(thermalmodel,tlist)

result1 = 
  TransientThermalResults with properties:

      Temperature: [1541x21 double]
    SolutionTimes: [0 0.5000 1 1.5000 2 2.5000 3 3.5000 4 4.5000 5 ... ]
       XGradients: [1541x21 double]
       YGradients: [1541x21 double]
       ZGradients: []
             Mesh: [1x1 FEMesh]

Check the currently active initial temperature specification.

tica = findThermalIC(thermalmodel.InitialConditions,"Face",1)

tica = 
  GeometricThermalICs with properties:

            RegionType: 'face'
              RegionID: 1
    InitialTemperature: 0

Now, resume the analysis and solve the problem for times from 10 to 15 seconds. Use the previously obtained solution for 10 seconds as an initial condition. Since 10 seconds is the last element in tlist, you do not need to specify the solution time index. By default, thermalIC uses the last solution index.

ic = thermalIC(thermalmodel,result1);

Solve the problem

tlist = 10:0.5:15;
result2 = solve(thermalmodel,tlist);

Check the currently active initial temperature specification.

tica = findThermalIC(thermalmodel.InitialConditions,"Face",1)

tica = 
  NodalThermalICs with properties:

    InitialTemperature: [1541x1 double]

pdeplot(thermalmodel,"XYData",tica.InitialTemperature)

Input Arguments

thermalmodel.InitialConditions — Initial conditions of a thermal model

InitialConditions property of a thermal model

Initial conditions of a thermal model, specified as the InitialConditions property of a ThermalModel object.

RegionType — Geometric region type

"Edge" | "Face" | "Vertex" | "Cell" for a 3-D model

Geometric region type, specified as "Edge", "Face", or "Vertex" for a 2-D model or 3-D model, or "Cell" for a 3-D model.

Data Types: char | string

RegionID — Geometric region ID

vector of positive integers

Geometric region ID, specified as a vector of positive integers. Find the region IDs using the pdegplot function with the "FaceLabels" (3-D) or "EdgeLabels" (2-D) value set to "on".

Data Types: double

Output Arguments

tica — Thermal initial condition for a particular region

GeometricThermalICs object | NodalThermalICs object

Thermal initial condition for a particular region, returned as a GeometricThermalICs Properties or NodalThermalICs Properties object.

Version History

Introduced in R2017a