mod_explicit_add_face_bc Module Reference

Functions/Subroutines
subroutine	explicit_add_face_bc (field, boundary_condition)
	Compute the ghost node values of a field depending on boundary conditions.

Function/Subroutine Documentation

explicit_add_face_bc()

subroutine mod_explicit_add_face_bc::explicit_add_face_bc	(	type(t_face_field), intent(inout)	field,
		type(t_boundary_condition_face), intent(in)	boundary_condition )

Compute the ghost node values of a field depending on boundary conditions.

The computation is done for Neumann and Dirichlet boundaries.

• The Neumann value is modified as to account for the wanted extrapolated derivative at the destination cells *.

This is done by applying a different Neumann condition which is the extrapolation of the derivative at the extrapolated point (order 2):

\[ \phi(\alpha) \simeq \phi(x_0) + \alpha D^1(x_0) + \alpha^2/2 D^2(x_0) \Rightarrow \frac{d \phi}{d x}(\alpha) \simeq D^1(x_0) + \alpha D^2(x_0) \Rightarrow D^1(x_0) \simeq \frac{d \phi}{d x}(\alpha) - \alpha D^2(x_0) \]

where \( \alpha \) is the distance between the extrapolation cell and the place where the derivative is given.

Example

if the right face is a Neumann boundary, then scalar(i,je+1,k) will be filled with the 2nd order extrapolated value at the face.

Parameters

[in,out]	field	face field.
[in]	boundary_condition	boundary conditions for the face field.