External Flow Imposed over a Rotating Disk
Geometrical arrangements with disks rotating with an angular velocity ω in a fluid, which rotates in the same direction with a velocity Ω different from ω, may be found in many technical applications such as parallel disks co-rotating with different angular velocities, disks rotating in swirling flows, etc. [114, 138, 139, 196]. If ω>Ω (or β=vϕ,∞/(ωr)<1), then fluid flow on the disk surface caused by rotation is radially outward (centrifugal). A schematic diagram of such flow is outlined in Fig. 5.1. Physically, flow for β<1 looks like flow over a free disk for β=0, with quantitative relations for the velocity and temperature fields being dependent on a particular non-zero value of β.