UNSOLVED PROBLEMS
PROBLEM 1: A simple flow system to be used for steady flow tests consists of a constant head tank connected to a length of 4-mm-diameter tubing s shown in the figure. The liquid has a viscosity of 0.015 N.s/m2, a density of 1200 kg/ m3, and discharges into the atmosphere with a mean velocity of 2 m/s. (a) Verify that the flow will be laminar.(b) The flow is fully developed in the last 3 m of the tube. What is the pressure at the pressure gage? (c) What is the magnitude of the wall shearing stress, 
, in the fully developed region?
PROBLEM 2: A diesel fuel filter, consists of a porous material in the form of a hollow cylinder of inner diameter 
, outer diameter 
and length L=20cm that is contained within a chamber that provides for a radial inflow of the fuel to be filtered. If the fuel flow rate is Q=1l/min, the fuel viscosity 
and the fuel filter permeability k=0.01 
, calculate the pressure drop 
required to force the fuel through the filter? Answer: (3.194e -2) Pa)
PROBLEM 3: A fluid of viscosity 0.5poise and specific gravity 1.2 is flowing through a circular pipe of diameter 100mm.The maximum shear stress at the pipe wall is given by 147.15 Ns/m2 find a) pressure gradient b)Average velocity c)Reynolds number of flow
Answer: a) -64746 N/m3 b) 3.678m/s c) 882.72
PROBLEM 4: Flow of standard air in laboratory wind tunnel. Teat section is 
square. Displacement thicknesses are 
and 
. Free stream speed i 
. Find the change in static pressure between sections (1) and (2).
ANS: (1.61 %)
PROBLEM 5: Flat-plate boundary-layer flow; turbulent flow from the leading edge. Assume 1/7 –power velocity profile.
ANS: (24.1mm, 3.01mm, 
)