Stokes’ flow elements neglect acceleration, and thus requires no additional stabilization.
Standard 6 node triangular element for stokes flow, with quadratic geometry, velocity and linear pressure. Both compressible and incompressible material behavior is supported (and also the seamless transition between the two). The element features are summarized in Table 55.
Keyword  Tr121Stokes 
Description  Standard 6 node triangular element for stokes flow, with quadratic geometry, velocity and linear pressure 
Specific parameters   
Unknowns  Unknown pressure in nodes 1–3 with unknown velocity (V_u and V_v) in all 6 nodes. 
Approximation  Quadratic approximation of geometry and velocity, linear pressure approximation. 
Integration 

Features   
Status  Reliable 
Standard 10 node tetrahedral element for stokes flow, with quadratic geometry, velocity and linear pressure. The element features are summarized in Table 56.
Keyword  Tet21Stokes 
Description  Standard 10 node tetrahedral element for stokes flow, with quadratic geometry, velocity and linear pressure 
Specific parameters   
Unknowns  Unknown pressure (P_f) in nodes 1–4, and unknown velocity (V_u, V_v, V_w) in all nodes. 
Approximation  Quadratic approximation of geometry and velocity, linear pressure approximation. 
Integration 

Features   
Status  Untested 
Standard 27 node hexahedral element for stokes flow, with quadratic geometry, velocity and linear pressure. The element features are summarized in Table 57.
Keyword  Hexa21Stokes 
Description  Standard 10 node tetrahedral element for stokes flow, with quadratic geometry, velocity and linear pressure 
Specific parameters   
Unknowns  Unknown pressure (P_f) in nodes 1–8, and unknown velocity (V_u, V_v, V_w) in all nodes. 
Approximation  Quadratic approximation of geometry and velocity, linear pressure approximation. 
Integration 

Features   
Status  Untested 
So called “Mini” element in 2D. A 3 node triangular element for stokes flow, with linear geometry and pressure. Velocity is enriched by a bubble function. Should not be used with materials that have memory (which is uncommon for flow problems). The element features are summarized in Table 58.
Keyword  Tr1BubbleStokes 
Description  So called “Mini” 2D element 
Specific parameters   
Unknowns  Unknown pressure (P_f) in all nodes, and unknown velocity (V_u, V_v) in all nodes and one internal dof manager. 
Approximation  Linear geometry and pressure. Velocity is enriched by a bubble function. 
Integration 

Features   
Status  Untested 
So called “Mini” element in 3D. A 4 node tetrahedral element for stokes flow, with linear geometry and pressure. Velocity is enriched by a bubble function. Should not be used with materials that have memory (which is uncommon for flow problems). The element features are summarized in Table 59.
Keyword  Tet1BubbleStokes 
Description  So called “Mini” 3D element 
Specific parameters   
Unknowns  Unknown pressure (P_f) in all nodes, and unknown velocity (V_u, V_v) in all nodes and one internal dof manager. 
Approximation  Linear geometry and pressure. Velocity is enriched by a bubble function. 
Integration 

Features   
Status  Untested 