Suspension Acoustics: An Introduction to the Physics of Suspensions

In the following formulas, A, B, C, and D represent vector functions;
and ? represent scalar functions.
If x= i x+ j y+ k z in the position vector of a point (x, y, z) and r= x, then:
In the following formulas, V is a volume bounded by a closed surface S, having a unit normal vector n directed outward from V:
Let S be an open surface with unit normal n, bounded by the closed contour C having a line element d I. Then,