HW_11_problems

# HW_11_problems - P5165 In turbulent ﬂow near a ﬂat wall...

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

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: P5165 In turbulent ﬂow near a ﬂat wall, the local velocity 217 7 P628 3 v varies only with distance 3‘ from the wall, wall shear stress 7,... and ﬂuid properties p and u. The following data were taken in the University of Rhode Island wind tunnel for airﬂow, p = 0.0023 slug/r13, [.L = 3.81 5-7 slug/(ft - s), and r“. : 0.029 Ibf/ftz: y, in 5 0.021 0.035 3 0.055 I 0.080 f 0.12 i 0.16 .2 7 l u. ft/s i 50.6 54 l 5 .6 i 59.7 r635 i 65.9 ((1) Plot these data in the form of dimensionless :1 versus dimensionless y, and suggest a suitable power-law curve ﬁt. (b) Suppose that the tunnel speed is increased until u = 90 ft/s at y = 0.11 in. Estimate the new wall shear stress, in lbf/ftz. For straightening and smoothing an airﬂow in a SO—em- diameter duct, the duct is packed with a “honeycomb” of thin straws of length 30 cm and diameter 4 mm, as in Fig. P628. The inlet ﬂow is air at 110 kPa and 20°C, moving at an average velocity of 6 m/s. Estimate the pressure drop across the honeycomb. Thousands of straws P628 1.40ch P652 The pipe ﬂow in Fig. P652 is driven by pressurized air in the tank. What gage pressure 121 is needed to provide a 20°C water ﬂow rate Q = 60 mS/h? ﬂ 30m rt Smooth pipe: Q = ——-p d 5 cm Open jet P652 P662 Water at 20°C is to be pumped through 2000 ft of pipe from reservoir 1 to 2 at a rate of 3 ft3/s, as shown in Fig. P662. If the pipe is cast iron of diameter 6 in and the pump is 75 percent gfﬁcient, what horsepower pump is needed? Pu P662 ® mp t *P6.102 A 70 percent efﬁcient pump delivers water at 20°C from one reservoir to another 20 ft higher, as in Fig. P6102. The piping system consists of 60 ft of galvanized iron 2— in pipe, 21 reentrant entrance, two screwed 90° long-radius elbows, a screwedvopen gate valve, and a sharp exit. What is the input power required in horsepower with and with— out a 6° well—designed conical expansion added to the exit? The flow rate is 0.4 nS/s. 6° cone ...
View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern