Problem 11.2
Given: Data on an air compressor Find: Whether or not the vendor claim is feasible Solution The data provided, or available in the Appendices, is: p1 = 101 kPa p2 = ( 650 + 101) kPa J cp = 1004 kg K T1 = ( 20 + 273) K T2 = ( 285 + 273
Problem 9.1 (In Excel)
Solution Governing equations: The critical Reynolds number for transition to turbulence is Re crit = VL crit/ = 500000
The critical length is then L crit = 500000/V Tabulated or graphical data: = = 3.79E-07 0.00234 (Table A.
Problem 8.1
Problem 8.2
Given: Data on air flow in duct Find: Volume flow rate for turbulence; entrance length Solution The given data is D = 0.25 m
2 -5 m
From Fig. A.3
= 1.46 10
s
The governing equations are Re = V D Recrit = 2300 Q = 4
Problem 7.4
Problem 7.5
Nondimensionalizing the velocity, pressure, spatial measures, and time:
u* =
u V
p* =
p p
x* =
x L
r* =
r L
t* = t
V L
Hence
L t* V
u =V u*
p = p p *
x = Lx*
r = Dr*
t=
Substituting into the governing equati
Problem 5.3
Problem 5.4
Problem 5.6
Problem 5.9
The x component of velocity in a steady incompressible flow field in the xy plane is u = Ax/(x2 + y2), where A = 10 m2/s, and x and y are measured in meters. Find the simplest y component of velocity
Problem 4.2
A mass of 3 kg falls freely a distance of 5 m before contacting a spring attached to the ground. If the spring stiffness is 400 N/m, what is the maximum spring compression?
Given: Data on mass and spring Find: Maximum spring compression
Problem 2.1
For the velocity fields given below, determine: (a) whether the flow field is one-, two-, or three-dimensional, and why. (b) whether the flow is steady or unsteady, and why. (The quantities a and b are constants.)
Solution (1) V = V (
1
Problem 1.2
2
Problem 1.3
3
Problem 1.4
4
5
Problem 1.6
Make a guess at the order of magnitude of the mass (e.g., 0.01, 0.1, 1.0, 10, 100, or 1000 lbm or kg) of standard air that is in a room 10 ft by 10 ft by 8 ft, and then compute this ma