Lab 3 Bernoulli Equation

1
Lab -3 Bernoulli Equation

• General Information
• Hand in Pre-lab Questions
• Worksheet and Spreadsheets due Thursday by 12
  noon
• Lab Reports due Tuesday by 3.00 pm

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• Objectives
• To investigate the validity of Bernoullis
  equation as applied
• to a tapering horizontal zone
• To determine if the variations in pressure can
  be predicted
• by Bernoullis equation for tapering horizontal
  zone

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Theory Bernoullis Equation
.(1)
If horizontal tube leveled correctly, then z1
z2, and equation 1 is then simplified to
..(2)

pressure head or static head hs
velocity head hv
Total head hT hs hv
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Assumptions

• Bernoulli made some assumptions for his equation
  to work
• Inviscid flow, constant viscosity (no shear
  stress in the tube)
• Flow is steady
• Points 1 and 2 which you are comparing are in
  the same streamline
• Density of the fluid is constant
• System is not accelerating
• Keep in mind these assumptions while taking
  measurements in the lab

5
76.08
55.46
15.8
7.4
2.9
5.0
f
b
c
d
e
a
Tube diameter (mm) a 25.0 b 13.9 c 11.8 d
10.7 e 10.0 f 25.0
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Main Objective Is Bernoullis equation
validated? Why/ Why not?  
Any assumptions violated?   In the Data
Sheet hsm static head measured and hTm total
head measured   Measurement Points
Diverging
Converging
Piezometer reads static heads or pressure
heads Pitot Probe total head Volume will be
taken using a volume of 5 L (because of time
concerns)
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Analysis

• Determine the three flow rates
• Calculate the velocity head at each cross section
• Calculate the best estimate of the true value of
  HT in the tube
• Predict the variation of static pressure head HSt
  along the length of the tube - Compare observed
  to predicted value
• Graph values of HT, HSt, HTot as a function of
  position along the tube
• Discuss the converging and diverging section and
  how the values change within them
• Discuss the effect of change in flow rate on
  observations
• Comment on validity of B.Eq. for convergent and
  divergent flows