A delivery car carries a long sign on the top, which can be considered as a thin plate (thin in the direction into the paper). The car is moving at 65miles/hour. (a) Is the boundary layer laminar or turbulent at the trailing edge? (b) If the boundary layer is laminar at the trailing edge, assume the entire boundary layer is laminar. If the boundary layer is turbulent at the trailing edge, assume the entire boundary layer is turbulent. Then estimate the drag on the sign (it has two sides!). (c) If the boundary layer is turbulent at the trailing edge, use the mixed boundary layer (laminar + turbulent) formula to estimate the drag (It has two sides!). Valid Range Cy = CDf = FD pUAw Phil's Pizza: 555-5748 Boundary layer flow over a flat plate formulas: Laminar -8 m- Turbulent ReL 5.105 5-105 < ReL < 107 107 < ReL < 10⁹ 0.371 (Re)1/5 5 (Re)1/2 0.664 (Re)1/2 1.328 (ReL)¹/2 0.0740 (ReL)1/5 0.0576 (Re)1/5 0.455 (log10 ReL) 2.58 60 cm Mixed 5.105 ReL < 10⁹ 0.455 (log10 ReL)2.58 - 1700 REL

A delivery car carries a long sign on the top, which can be considered as a thin plate (thin in the direction into the paper). The car is moving at 65miles/hour. (a) Is the boundary layer laminar or turbulent at the trailing edge? (b) If the boundary layer is laminar at the trailing edge, assume the entire boundary layer is laminar. If the boundary layer is turbulent at the trailing edge, assume the entire boundary layer is turbulent. Then estimate the drag on the sign (it has two sides!). (c) If the boundary layer is turbulent at the trailing edge, use the mixed boundary layer (laminar + turbulent) formula to estimate the drag (It has two sides!). Valid Range Cy = CDf = FD pUAw Phil's Pizza: 555-5748 Boundary layer flow over a flat plate formulas: Laminar -8 m- Turbulent ReL 5.105 5-105 < ReL < 107 107 < ReL < 10⁹ 0.371 (Re)1/5 5 (Re)1/2 0.664 (Re)1/2 1.328 (ReL)¹/2 0.0740 (ReL)1/5 0.0576 (Re)1/5 0.455 (log10 ReL) 2.58 60 cm Mixed 5.105 ReL < 10⁹ 0.455 (log10 ReL)2.58 - 1700 REL

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.55P

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