2D CBS Elements¶

2D CBS Elements¶

Tr1CBS element¶

Represents the linear triangular finite element for transient incompressible flow analysis using cbs algorithm with equal order approximation of velocity and pressure fields. Each node has 3 degrees of freedoms (two components of velocity and pressure). The node numbering is anti-clockwise. The element features are summarized in Table Table 64.

Figure made with TikZ

Fig. 27 Tr1CBS element. Node numbering, Side numbering and definition of local edge c.s.(a).

Table 64 Tr1CBS element summary¶
Keyword	Tr1CBS
Description	linear triangular finite element for transient incompressible flow analysis using cbs algorithm
Specific parameters	[`bsides` (ia)] [`bcodes` (ia)]
Parameters	Since the problem formulation requires to evaluate some boundary terms, the element boundary edges should be specified as well as the types of boundary conditions applied at these boundary edges. The boundary edges (their numbers) are specified using `bsides` array. The type of boundary condition(s) applied to corresponding boundary side is determined by `bcodes` array. The available/supported boundary codes are following: 1 for prescribed traction, 2 for prescribed normal velocity, 4 for prescribed tangential velocity, and 8 for prescribed pressure. If the element side is subjected to a combination of these fundamental types boundary conditions, the corresponding code is obtained by summing up the corresponding codes.
Unknowns	Two velocity components (V_u and V_v) and pressure (P_f) are required in each node.
Approximation	Equal order approximation of velocity and pressure fields.
Integration	exact
Features	Constant boundary tractions are supportedfootnoteIn CBS algorithm formulation the prescribed traction boundary condition leads indirectly to pressure boundary condition in nodes associated to loaded edge. Such boundary condition is represented by PrescribedTractionPressureBC. See section on boundary conditions in OOFEM input manual.. Body loads representing the self-weight load are supported.
Status	Untested
Tests/Examples	fm/cbs3.in, fm/cbs1.in, fm/cbs2.in