suzerain: #2997 remove v_w from {rho v}_D

Also includes energy-related write ups and percolating
changes into the nondimensional portion of the model document

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44115 0bd85f0b-c151-43b9-a1e9-27231104551f