Boundaryconditions context

The context

The boundaryconditions context is for defining boundary conditions.

<dirichlet>

Use this to define Dirichlet-type boundary conditions.

• Attributes:  set - The topologyset to apply the boundary condition to  comp - The components to apply the boundary conditions to (one indexed, string with 1, 2, 3 or combinations)  type - The type of the boundary condition specification (anasol, expression, constant)    Here anasol only makes sense for problems where a known analytic solution is available  axes - The coordinate system to use when applying the boundary condition (global, local, local projected)  t1 - If using local axes in 3D, this is the first tangent direction (x,y,z)
• Value: A constant number or a function expression, in accordance with the given type. A blank value gives a homogenous Dirichlet condition.

See the expression functions page for the symbolic expression syntax.

Example:

  <dirichlet set="foo" comp="1"/>
  <dirichlet set="foo" comp="123" type="anasol"/>
  <dirichlet set="foo" comp="123" type="expression">x*y*z</dirichlet>

<neumann>

Use this to define Neumann-type boundary conditions.

Attributes:  * set - The topologyset to apply the boundary condition to  * type - The type of the boundary condition specification (anasol, expression, constant, linear)  * direction - The direction of the Neumann condition for vector fields (0 = along normal, 1,2,3 for a given global coordinate direction) Value: * The constant, slope or expression function in accordance with the given type.

See the expression functions page for the symbolic expression syntax.

Example:

  <neumann set="foo" type="anasol"/>
  <neumann set="foo" type="constant" direction="1">10</neumann>
  <neumann set="foo" type="expression" direction="0">x*y*z</neumann>