1030 as q2 3 gyc gycy2 c v2y2 c c 1032 by comparison

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Unformatted text preview: is impossible physically. For E Emin two solutions are possible: (1) large depth with V Vc, called subcritical, and (2) small depth with V Vc, called supercritical. In subcritical flow, disturbances can propagate upstream because wave speed C0 V. In supercritical flow, waves are swept downstream: Upstream is a zone of silence, and a small obstruction in the flow will create a wedge-shaped wave exactly analogous to the Mach waves in y Constant q Horizontal hf y=E EGL E v v Subcritical yc Fig. 10.8 Specific-energy considerations: (a) illustration sketch; (b) depth versus E from Eq. (10.29), showing minimum specific energy occurring at critical depth. | V2 2g Critical y Supercritical 0 (b) (a) | e-Text Main Menu E E min | Textbook Table of Contents | Study Guide 10.4 Specific Energy; Critical Depth 673 Fig. 9.18c.2 The angle of these waves must be 1 sin c0 V 1 sin (gy)1/2 V (10.34) The wave angle and the depth can thus be used as a simple measurement of supercritical-flow velocity. Note from Fig. 10.8b that small changes in E...
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This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.

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