vertexIC

Initial conditions on geometry vertex

Since R2023a

Description

A vertexIC object specifies the type of initial condition on a vertex of a geometry. An femodel object contains an array of vertexIC objects in its VertexIC property.

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.VertexIC(VertexID) = vertexIC(Name=Value)

model.VertexIC = vertexIC(Name=Value)

Description

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

model.VertexIC = vertexIC(Name=Value) assigns the specified initial condition to all vertices of the geometry. For example, model.VertexIC = vertexIC(Temperature=25) specifies the initial temperature on all vertices.

model.VertexIC = vertexIC(Temperature = 25)

Input Arguments

VertexID — Vertex IDs

vector of positive integers

Vertex IDs, specified as a vector of positive integers. Find the vertex IDs using pdegplot with the VertexLabels value set to "on".

Data Types: double

Properties

Displacement — Initial displacement

numeric vector | function handle

Initial displacement, specified as a numeric vector or function handle. 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.

The default initial displacement is zero.

Velocity — Initial velocity

numeric vector | function handle

Initial velocity, specified as a numeric vector or function handle. 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.

The default initial velocity is zero.

Temperature — Initial temperature or initial guess for temperature

real number | function handle

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

Examples

Initial Displacement

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

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

model = femodel(AnalysisType="structuralTransient", ...
                Geometry=@squareg);

Plot the geometry with the vertex labels.

pdegplot(model.Geometry,VertexLabels="on");
xlim([-1.1 1.1])
ylim([-1.1 1.1])

The default initial displacement on the entire geometry is zero. Specify a small nonzero initial displacement on vertex 1.

model.VertexIC(1) = vertexIC(Displacement=[0 10^(-5)]);
model.VertexIC

ans = 
  1x4 vertexIC array

Properties for analysis type: structuralTransient

Index     Displacement     Velocity    Temperature
  1      [0 1.0000e-05]       []           []     
  2            []             []           []     
  3            []             []           []     
  4            []             []           []     

  Show all properties

Initial Temperature

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

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

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

Plot the geometry with the vertex labels.

pdegplot(model.Geometry,VertexLabels="on");
xlim([-1.1 1.1])
ylim([-1.1 1.1])

Because there is no default initial temperature, you must specify the initial temperature for the entire geometry.

model.FaceIC = faceIC(Temperature=0);
model.FaceIC

ans = 
  1x1 faceIC array

Properties for analysis type: thermalTransient

Index    Temperature
  1           0     

  Show all properties

Specify a small nonzero initial temperature on all corners of the square.

model.VertexIC = vertexIC(Temperature=0.1);
model.VertexIC

ans = 
  1x4 vertexIC array

Properties for analysis type: thermalTransient

Index    Temperature
  1        0.1000   
  2        0.1000   
  3        0.1000   
  4        0.1000   

  Show all properties

Version History

Introduced in R2023a