Chapter 9, Problem 25P

In Example 9-6 we derive the equation for volumetric stain rate, $\left(1/V\right)\left(DV/Dt\right)=\stackrel{\to }{V}\cdot \stackrel{\to }{\nabla }$ . Write this as a word equation and discuss what happens to the volume of a fluid element as it moves around in a compressible fluid flow field (Fig.9-25).

FIGURE P9-25