High Reynolds Number Flow

Having discussed viscous flow at low Reynolds numbers, we now turn our attention to the diametrically opposite limit of inertia-dominated flow at high Reynolds numbers. Inspecting the changes in the structure of a flow with in- creasing Reynolds number, we encounter a rich phenomenology and a variety of transition protocols. In all cases, when the Reynolds number exceeds a critical threshold, flow instability occurs and a small-scale turbulent motion is established. The theoretical study of the structure and dynamics of flows at high Reynolds numbers encompasses several complementary topics including potential flow theory, boundary layer analysis, hydrodynamic stability, turbu- lent motion, and dynamics of vortex motion. Potential flow was considered earlier in this book; boundary layer theory, hydrodynamic stability, and tur- bulent motion will be discussed in this chapter; and vortex motion will be the exclusive topic of chapter 11.