Fundamentals of Aerodynamics
6th Edition
ISBN: 9781259129919
Author: John D. Anderson Jr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 19, Problem 19.2P
For the case in Problem 19.1, calculate the boundary-layer thickness at the trailing edge for
a. Completely laminar flow
b. Completely turbulent flow
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Problem 1. A smooth plate with length L = 3.0 m and width b = 0.90 m moves through still air at STP at a velocity of
U = 4.5 m/s that is aligned with L. Calculate the following for a boundary layer that stays laminar and for one that
trips to turbulent at the leading edge: (a) boundary layer disturbance thickness, 8, at
x = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 m from the leading edge of the plate, (b) wall shear stress, Tw, at those æ-
locations, and (c) friction drag, Fp.f, on one side of plate. (d) Calculate percent decrease in drag for laminar versus
turbulent boundary layer.
Problem 3:
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
8/x
C₁=PU²
CDf =
FD
Phil's Pizza: 555-5748
Boundary layer flow over a flat plate formulas:
Laminar
8 m-
5
(Re)1/2
REL 5-105 5-105 < ReL < 107 107 < Ret < 10⁹
0.371
(Re)1/5
0.664
(Re)1/2
1.328
(ReL)1/2
Turbulent
0.0740
(ReL)1/5
0.0576
(Re)1/5
0.455
(log10 Rez) 2.58
60 cm
Mixed
5-105 ReL < 10⁹
0.455
(log10 ReL) 2.58
1700…
Aircraft flying at an altitude of (3 Km) with a velocity of (100 m/sec). The planform area of
the wing is (206 m² ). Find the overall drag force acting on this aircraft if you have the
following data :-
Aspect ratio= 10,
Weight of the aircraft = 7.5 x 105 kg.m/s²
Span efficiency factor = 0.95
Wing cross section is NACA 4412 airfoll
Drag coefficient = 0.006
Chapter 19 Solutions
Fundamentals of Aerodynamics
Ch. 19 - The wing on a Piper Cherokee general aviation...Ch. 19 - For the case in Problem 19.1, calculate the...Ch. 19 - For the case in Problem 19.1, calculate the...Ch. 19 - Consider Mach 4 flow at standard sea level...Ch. 19 - Repeat Problem 19.4 for the case of all turbulent...Ch. 19 - Prob. 19.6PCh. 19 - Prob. 19.7P
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