Prev Subsection 4.9.1: Guidelines for Biphasic-Solute Analyses Up Subsection 4.9.1: Guidelines for Biphasic-Solute Analyses Subsubsection 126.96.36.199: Prescribed Initial Conditions Next
188.8.131.52 Prescribed Boundary Conditions
In most analyses, it may be assumed that the ambient fluid pressure in the external environment is zero, thus , where the subscripted asterisk is used to denote environmental conditions. The ambient solute concentration may be represented by . It follows that the effective fluid pressure in the external environment is and the effective concentration is . Therefore, in biphasic-solute analyses, whenever the external environment contains a solute at a concentration of , the user must remember to prescribe non-zero boundary conditions for the effective solute concentration and the effective fluid pressure.
Letting also implies that prescribed mixture normal tractions (Section 184.108.40.206↑) represent only the traction above ambient conditions. Note that users are not obligated to assume that . However, if a non-zero value is assumed for the ambient pressure, then users must remember to incorporate this non-zero value whenever prescribing mixture normal tractions.