faceIC

Initial conditions on geometry face

Since R2023a

Description

A faceIC object specifies the type of an initial condition on a face of a geometry. An femodel object contains an array of faceIC objects in its FaceIC property.

faceIC 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.FaceIC(FaceID) = faceIC(Name=Value)

model.FaceIC = faceIC(Name=Value)

Description

model.FaceIC(FaceID) = faceIC(Name=Value) creates a faceIC 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 faces of the geometry stored in the femodel object model. For example, model.FaceIC([1 2]) = faceIC(Temperature = 25) specifies the temperature on faces 1 and 2.

model.FaceIC = faceIC(Name=Value) assigns the specified initial condition to an entire 2-D geometry or to all faces of a 3-D geometry. For example, model.FaceIC = faceIC(Temperature = 25) specifies the initial temperature on all faces.

Input Arguments

FaceID — Face IDs

vector of positive integers

Face IDs, specified as a vector of positive integers. Find the face IDs using pdegplot with the FaceLabels value set to "on".

Data Types: double

Properties

Displacement — Initial displacement

numeric vector | function handle | StaticStructuralResults object | TransientStructuralResults object

Initial displacement, specified as a numeric vector, function handle, StaticStructuralResults object, or TransientStructuralResults object created by using solve. A numeric vector must contain two elements for a 2-D model and three elements for a 3-D model. The elements represent the components of initial displacement.

Use a function handle to specify spatially varying initial displacement. The function must return a two-row matrix for a 2-D model and a three-row matrix for a 3-D model. 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, faceIC 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.

Velocity — Initial velocity

numeric vector | function handle | StaticStructuralResults object | TransientStructuralResults object

Initial velocity, specified as a numeric vector, function handle, StaticStructuralResults object, or TransientStructuralResults object created by using solve. A numeric vector must contain two elements for a 2-D model and three elements for a 3-D model. The elements represent the components of initial velocity.

Use a function handle to specify spatially varying initial velocity. The function must return a two-row matrix for a 2-D model and a three-row matrix for a 3-D model. 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, faceIC 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.

Temperature — Initial temperature or initial guess for temperature

real number | function handle | SteadyStateThermalResults object | TransientThermalResults object

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, faceIC applies the results to the entire geometry. For TransientThermalResults, you can access results for a particular time-step by using the filterByIndex function.

MagneticVectorPotential — Initial guess for magnetic potential in nonlinear magnetostatic problem

positive number | function handle | MagnetostaticResults object

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

NormFluxDensity — Initial flux density

positive number | function handle

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

Initial Flux Density

Specify initial flux density for an femodel object representing a nonlinear magnetostatic problem.

Create an femodel object for solving a magnetostatic problem, and assign the L-shaped membrane geometry to the model.

model = femodel(AnalysisType="magnetostatic", ...
                Geometry=@lshapeg);

Plot the geometry with the face labels.

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

Specify the initial flux density for the entire geometry.

model.FaceIC = faceIC(NormFluxDensity=1.5);
model.FaceIC

ans = 
  1x3 faceIC array

Properties for analysis type: magnetostatic

Index    MagneticVectorPotential    NormFluxDensity
  1                []                   1.5000     
  2                []                   1.5000     
  3                []                   1.5000     

  Show all properties

Specify the initial flux density on face 1.

model.FaceIC(1) = faceIC(NormFluxDensity=5);
model.FaceIC

ans = 
  1x3 faceIC array

Properties for analysis type: magnetostatic

Index    MagneticVectorPotential    NormFluxDensity
  1                []                      5       
  2                []                   1.5000     
  3                []                   1.5000     

  Show all properties

Nonconstant Initial Temperature

Specify an initial temperature that depends on coordinates.

Create a rectangular geometry.

gm = decsg([3 4 -1.5 1.5 1.5 -1.5 0 0 .2 .2]');

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

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

Set the initial temperature in the rectangle to be dependent on the y-coordinate, for example, ${10}^3\left(0.2-{\mathit{y}}^2\right)$.

T0 = @(location)10^3*(0.2 - location.y.^2);
model.FaceIC = faceIC(Temperature=T0);
model.FaceIC

ans = 
  1x1 faceIC array

Properties for analysis type: thermalTransient

Index                Temperature            
  1      @(location)10^3*(0.2-location.y.^2)

  Show all properties

Version History

Introduced in R2023a