- #1
phdggg
- 1
- 0
Hi all,
One thing I am really confused is the relation between incompressiblity and divergence-free. Since I am coding a finite element code that use mixed displacement and pressure formulation. From what I got from your book. Both incompressible solid and fluid can be characterized by divergence-free vector field (displacement for solid and velocity for fluid). But is this only for small deformation in the case of solid? Since for large deformation, the determinant of deformation gradient must be one, which seems not equivalent to divergence-free.
What about for fluid, because it uses Eularian frame, the divergence-free should be equivalent to incompressibility for any case. Is this correct? Thanks in advance for your clarification!
Mengda
One thing I am really confused is the relation between incompressiblity and divergence-free. Since I am coding a finite element code that use mixed displacement and pressure formulation. From what I got from your book. Both incompressible solid and fluid can be characterized by divergence-free vector field (displacement for solid and velocity for fluid). But is this only for small deformation in the case of solid? Since for large deformation, the determinant of deformation gradient must be one, which seems not equivalent to divergence-free.
What about for fluid, because it uses Eularian frame, the divergence-free should be equivalent to incompressibility for any case. Is this correct? Thanks in advance for your clarification!
Mengda
