4 read for water reynolds number is red vd q a 00111

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: ) ft]2 2 1.01 From Table 1.4 read for water Reynolds number is 10 6 m2/s 1.09 (8.17 ft/s)[( 1 /12) ft] 2 1.09 10 5 ft2/s 10 5 ft2/s. Then the pipe 31,300 This is greater than 4000; hence the flow is fully turbulent, and Eq. (6.6) applies for entrance length Le d 4.4 Re1/6 d (60 ft)/[( 1 /12) ft] 2 The actual pipe has L/d tion Le L 25 1440 (4.4)(31,300)1/6 25 1440. Hence the entrance region takes up the frac- 0.017 1.7% Ans. This is a very small percentage, so that we can reasonably treat this pipe flow as essentially fully developed. Shortness can be a virtue in duct flow if one wishes to maintain the inviscid core. For example, a “long” wind tunnel would be ridiculous, since the viscous core would invalidate the purpose of simulating free-flight conditions. A typical laboratory lowspeed wind-tunnel test section is 1 m in diameter and 5 m long, with V 30 m/s. If we take air 1.51 10 5 m2/s from Table 1.4, then Red 1.99 106 and, from Eq. (6.6), Le/d 49. The test section has L/d 5, which is much...
View Full Document

This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.

Ask a homework question - tutors are online