Chapt06

Thus transition is specified at vd 2300 with d known

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: / 2300. With d known, we introduce the appropriate fluid properties at 20°C from Tables A.3 and A.4: (a) Air: (b) Water: Vd (1.205 kg/m3)V(0.05 m) 1.80 E-5 kg/(m s) Vd (998 kg/m3)V(0.05 m) 0.001 kg/(m s) 2300 2300 or V or V 0.7 m s 0.046 m s These are very low velocities, so most engineering air and water pipe flows are turbulent, not laminar. We might expect laminar duct flow with more viscous fluids such as lubricating oils or glycerin. | v v In free surface flows, turbulence can be observed directly. Figure 6.2 shows liquid flow issuing from the open end of a tube. The low-Reynolds-number jet (Fig. 6.2a) is smooth and laminar, with the fast center motion and slower wall flow forming different trajectories joined by a liquid sheet. The higher-Reynolds-number turbulent flow (Fig. 6.2b) is unsteady and irregular but, when averaged over time, is steady and predictable. | e-Text Main Menu | Textbook Table of Contents | Study Guide 6.1 Reynolds-Number Regimes 327 Fig. 6.2 Flow issuing at constant speed from a pipe...
View Full Document

Ask a homework question - tutors are online