conclusion

CONCLUSIONS (Student 1)

This section should include a clear, concise statement of the significant findings of the work, generally in order of importance. The conclusions are taken from the major points of the discussion. Conclusions are frequently followed by recommendations for improving the experimental procedure or for future work, building on the results of the study. Recommendations should be specific and justified technically by the results and discussion of the experiment.

Results

Experimental Data

Analysis of Experimental Data

As shown in the figure below, it is apparent that the right side and left side of the variation share an inverse correlation. We calculated the variation using equation 12 and compared it to the theoretical variation. We were given both A1 and A5 to calculate the theoretical variation.  We found that the theoretical variation gave a

gave a negative results.

Figure 1 - Variation Comparison

From the figure shown below, we can see that the plot is quite steady for the low discharge pressure head compared to the high discharge plot. For the low discharge plot, the measured and calculated pressure head are relatively horizontal until about point 5 where it starts to drop. As for the high discharge plot, the values for calculated and measured are not consistent. We used equation 3 to calculate the pressure head.

Figure 2a – Pressure head

Figure 2b – Pressure head

Using the measured and theoretical flow rates, the discharge was determined using a linear regression analysis. The correlation are positive for both the low and high discharge plot. Equation 6 and 7 were used to calculate the flow rate.

Figure 3a – Flow rate

Figure 3b – Flow rate

Discussion

For the divergent flow, it is not valid along the 14 degree tapered section upstream because there is a large fluctuation between point 5 and 6 and also the static and total pressure must maintain its accuracy.. However, for the converging flow it is valid at 21 degree tapered section upstream because the difference between the values on point 1 and 2 are minimal. The assumptions made in deriving the Bernoulli equation are incompressible, frictionless and steady flow. As shown in the table, the static head and dynamic head both fluctuated greatly from one point to another. Also, the velocities increases steadily from point 1 to point 5 but drops significantly at point 6.

The difference between the measured and the predicted total pressure head loss could be due to human error alone or a combination with inconsistent flow. We noticed that during the experiment the water pump did not run properly. Calculation wise, the resolution of the manometers was five millimeters, so this is subject to human error. Also, the values differ because of the the variation in the viscosity. From this, the data was enough to be compromised.

From figure 2a & 2b, it is safe to say that figure 2a is a laminar, converging flow. From figure 2a, the values are parallel to each other where it fluctuates minimally from one point to another which follows Bernoulli’s principle. However, values for the measured and calculated values for pressure head fluctuates largely and doesn’t obey they Bernoulli’s principle.

To use Bernoulli’s equation to predict pressure in the converging section of the tube, the static and total pressure must be known for at least one point. With only the flow rate and geometry, our calculation will be limited. To use the Bernoulli’s equation properly, there must be at least 3 known values of pressures at a given point.

In summary, the team believes that this experiment was a success overall. The pressure decrease at the converged section of the tube due to the increase in velocity. As shown in figure 2a, the total pressure head is relatively similar throughout the tube. Also from figure 2a, the predicted values of total pressure is larger than the measured values.