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cellIC

Initial conditions on geometry cell

Since R2023a

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Description

A cellIC object specifies the type of an initial condition on a cell of a geometry. An femodel object contains an array of cellIC objects in its CellIC property.

cellIC applies these rules for initial condition assignments:

  • You can use a geometric assignment to associate the initial condition with the specified geometric regions or the entire geometry.

  • You must apply a results-based assignment to all geometric regions because the results object contains information about the entire geometry.

  • For separate assignments to a geometric region (or the entire geometry) and the boundaries of that region, the solver uses the specified assignment on the region and chooses the assignment on the boundary as follows. The solver gives an EdgeIC assignment precedence over a FaceIC assignment, even if you specify a FaceIC assignment after an EdgeIC assignment. The assignments in order of precedence are VertexIC (highest precedence), EdgeIC, FaceIC, and CellIC (lowest precedence).

Creation

Syntax

model.CellIC(CellID) = cellIC(Name=Value)
model.CellIC = cellIC(Name=Value)

Description

model.CellIC(CellID) = cellIC(Name=Value) creates a cellIC object and sets properties using one or more name-value arguments. This syntax assigns the specified structural, thermal, or electromagnetic initial condition to the specified cells of the geometry stored in the femodel object model. For example, model.CellIC([1 2]) = cellIC(Temperature=25) specifies the temperature on cells 1 and 2.

example

model.CellIC = cellIC(Name=Value) assigns the specified initial condition to the entire geometry. For example, model.CellIC = cellIC(Temperature = 25) specifies the initial temperature on all cells of the geometry.

example

Input Arguments

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Cell IDs, specified as a vector of positive integers. Find the cell IDs using pdegplot with the CellLabels value set to "on".

Data Types: double

Properties

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Initial displacement, specified as a numeric vector of three elements, function handle, StaticStructuralResults object, or TransientStructuralResults object created by using solve. The elements of the numeric vector represent the x-, y-, and z-components of initial displacement.

Use a function handle to specify spatially varying initial displacement. The function must return a three-row matrix. Each column of the matrix corresponds to the initial displacement at the coordinates provided by the solver. For details, see Nonconstant Parameters of Finite Element Model.

When you specify initial displacement as a StaticStructuralResults or TransientStructuralResults object, cellIC applies the results to the entire geometry. For TransientStructuralResults, you can access results for a particular time-step by using the filterByIndex function.

The default initial displacement is zero.

Initial velocity, specified as a numeric vector of three elements, function handle, StaticStructuralResults object, or TransientStructuralResults object created by using solve. The elements of the numeric vector represent the x-, y-, and z-components of initial velocity.

Use a function handle to specify spatially varying initial velocity. The function must return a three-row matrix. Each column of the matrix corresponds to the initial velocity at the coordinates provided by the solver. For details, see Nonconstant Parameters of Finite Element Model.

When you specify initial velocity as a StaticStructuralResults or TransientStructuralResults object, cellIC applies the results to the entire geometry. For TransientStructuralResults, you can access results for a particular time-step by using the filterByIndex function.

The default initial velocity is zero.

Initial temperature or initial guess for temperature, specified as a real number, function handle, SteadyStateThermalResults object, or TransientThermalResults object. Use a function handle to specify spatially varying initial temperature. For details, see Nonconstant Parameters of Finite Element Model.

When you specify initial temperature as a SteadyStateThermalResults or TransientThermalResults object, cellIC applies the results to the entire geometry. For TransientThermalResults, you can access results for a particular time-step by using the filterByIndex function.

Initial guess for magnetic potential in a nonlinear magnetostatic problem, specified as a column vector of three elements, a function handle, or a MagnetostaticResults object. Use a function handle to specify spatially varying initial magnetic potential. For details, see Nonconstant Parameters of Finite Element Model.

Initial flux density, specified as a positive number or a function handle. Use a function handle to specify an initial flux density that depends on the coordinates, magnetic potential and its gradients, and the norm of magnetic flux density. For details, see Nonconstant Parameters of Finite Element Model.

If a relative permeability, current density, or magnetization for the model depend on the magnetic potential or its gradients (state.u, state.ux, and so on), then initial conditions must not depend on the magnetic flux density (state.NormFluxDensity).

Examples

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Open Live Script

Specify initial temperature on a cell for an femodel object representing a transient thermal problem.

Create and plot a geometry that consists of two nested cylinders.

gm = multicylinder([0.01,0.015],0.05);
gm = rotate(gm,90,[0 0 0],[0 1 0]);
pdegplot(gm,CellLabels="on",FaceAlpha=0.4);

Figure contains an axes object. The axes object contains 6 objects of type quiver, text, patch, line.

Create an femodel object for solving a transient thermal problem, and assign the geometry to the model.

model = femodel(AnalysisType="thermalTransient", ...
                Geometry=gm);

Specify the initial temperature for the inner cylinder.

model.CellIC(1) = cellIC(Temperature=100);
model.CellIC
ans = 
  1x2 cellIC array

Properties for analysis type: thermalTransient

Index    Temperature
  1          100    
  2          []     

  Show all properties
Open Live Script

Specify initial displacement on a beam geometry for an femodel object representing a transient structural problem.

Create and plot a beam geometry.

gm = multicuboid(0.06,0.005,0.01);
pdegplot(gm,FaceLabels="on", ...
            CellLabels="on", ...
            FaceAlpha=0.4);

Figure contains an axes object. The axes object contains 6 objects of type quiver, text, patch, line.

Create an femodel object for solving a static structural problem, and assign the geometry to the model.

model = femodel(AnalysisType="structuralStatic", ...
                Geometry=gm);

Specify Young's modulus, Poisson's ratio, and the mass density.

model.MaterialProperties = materialProperties(YoungsModulus=210e3, ...
                                              PoissonsRatio=0.3, ...
                                              MassDensity=2.7e-6);

Apply the boundary condition and static load.

model.FaceBC(5) = faceBC(Constraint="fixed");
model.FaceLoad(3) = faceLoad(SurfaceTraction=[0 1e6 0]);

Generate a mesh and solve the model.

model = generateMesh(model,Hmax=0.02);
Rstatic = solve(model);

Change the analysis type of the model to structural transient.

model.AnalysisType = "structuralTransient";

Specify the initial condition using the static solution.

model.CellIC = cellIC(Displacement=Rstatic);
model.CellIC
ans = 
  1x1 cellIC array

Properties for analysis type: structuralTransient

Index              Displacement               Velocity    Temperature
  1      [1x1 pde.StaticStructuralResults]       []           []     

  Show all properties
Open Live Script

Specify initial magnetic potential for an femodel object representing a nonlinear magnetostatic problem.

Create an femodel object for solving a magnetostatic problem, and assign a geometry consisting of four hollow cylinders to the model.

model = femodel(AnalysisType="magnetostatic", ...
                Geometry="DampingMounts.stl");

Plot the geometry with the cell labels.

pdegplot(model.Geometry,CellLabels="on");

Figure contains an axes object. The axes object contains 6 objects of type quiver, text, patch, line.

Specify the initial magnetic potential for the entire geometry.

model.CellIC = cellIC(MagneticVectorPotential=[0.1 0.1 0]);
model.CellIC
ans = 
  1x4 cellIC array

Properties for analysis type: magnetostatic

Index    MagneticVectorPotential    NormFluxDensity
  1         [0.1000 0.1000 0]             []       
  2         [0.1000 0.1000 0]             []       
  3         [0.1000 0.1000 0]             []       
  4         [0.1000 0.1000 0]             []       

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Specify the initial magnetic potential for cell 1.

model.CellIC(1) = cellIC(MagneticVectorPotential=[0.2 0.1 0]);
model.CellIC
ans = 
  1x4 cellIC array

Properties for analysis type: magnetostatic

Index    MagneticVectorPotential    NormFluxDensity
  1         [0.2000 0.1000 0]             []       
  2         [0.1000 0.1000 0]             []       
  3         [0.1000 0.1000 0]             []       
  4         [0.1000 0.1000 0]             []       

  Show all properties

Version History

Introduced in R2023a

See Also

Objects

Functions