Volume averaging for the three components (two solid and one fluid) yields
- p_AK_A = B<>u_A - _A(1-_A),
- p_BK_B = B<>u_B - _B(1-_B), and
- p_fK_f = B<>u_f + . These three equations should be compared to (solids) and (fluidf). Now, to provide some further insight, notice that the left hand side of (uA) is equal to , while the right hand side is .