August 2014 Mission Statement Background
Error Analysis and Recommendations for Further Work
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5.3 Error Analysis and Recommendations for Further WorkThere were two problems that were noticed while testing the suction flow rates. The first was that the process of timing it might not have been accurate due to the time taking the hose to and from the collecting bucket and possibly letting air in. More advanced flow rate measuring equipment would have improved the measurement accuracy and experimental influences. Secondly, small air bubbles coming from the vacuum hose were observed in collecting beaker, suggesting a small air leak. This is seen in the drawn box in Figure 31. This would have had negative effect on the vacuum, and furthermore the suction. 
Figure 31 Air bubbles from vacuum hose Additionally, the suction flow rates would be very high for a full-scale anchor leg. But the small-grained Kiln sand would realistically be similar to small pebbles when scaled up. Flow rates are assumed to be lower if the sand grain size was smaller to model scaling for anchor leg and sand particles properly. However, this would have required using Silica flour, which was identified to cause health risk. The minimum fluidisation velocity calculation in section 3.4 was assuming Reynolds number is less than one, however, further calculations using stokes law to find Reynolds number proved this to be wrong. Although, the density part of the Ergun equation would have been small, this should be included in future work. Velocity of sand particles in the water should have been investigated to see the proportion of particles that are 0.5 mm and what proportion is less. Assumptions regarding pressure were common during the experiments. This was wished to be investigated further, especially to see if the pressure outside the anchor leg became more constant after an hour to compare it with theory. Comparing the pressure at the outside of the anchor leg to the inside would have provided an insight of the suction force due to pressure difference. However, this could not be done due to being unable to get hold of the required equipment such as pressure transducers. This is something that would be useful to investigate if this project would be taken forward for more experiments. An error was found, that for every experiment, more sand was clogging the system and affecting the results. This was known from using the y-tap, where it was evident that sand was building up since it became more difficult to change settings. For future work, it is recommended that a small tripod would be modelled. The results indicate that the methods works and the model tripod could be directly compared with this project. However, more work must be focused on reducing the flow rates during suction. It is advised that a layer of clay or at least a plastic sheet will be placed on top of sand to ensure less variation and reduction in flow rate. A vacuum pump may also be a possible option for testing, since suction would be more controlled. It was also acknowledged during the experiments that a see-through water tank would achieve a clearer view of the fluidisation and the suction process, as seen in the experimental testing of sharp sand in Figure 11. This would have enabled an increased understanding of volume of sand been fluidised and also what proportion of the seabed is greatly affected by the suction force. This could have also been achieved by using water-adapted microphone to hear the difference in the movement of sand particles at various locations. More varieties of anchor legs should be tested, investigating the affect of changing number of holes diameter sizes. The number of holes was briefly investigated by increasing the number, and even though the gripping force increased to 169 N, the flow rates increased. Fewer holes should therefore be tested to find an acceptable balance between flow rates and gripping force. Positioning of holes should be evaluated as well. Furthermore, for future work the navy ratings mentioned in the literature review, where a traditional anchor should have a mooring capacity of fifteen times its weight could be compared with this anchor. It should be stronger than these rating, and should therefore be weighed and compared to its average gripping force. There are various grades of concrete, where 55 MPa capacity concrete should be used on a model for testing. It is one of the stronger grades, which would be able to resist the force of 100-year Atlantic wave. Finally, a tripod model of the best output in terms of holes sizes and number should be tested in a real seabed for a wide range of time periods. This would test its gripping under real sources of impact. Directory: shs shs -> Stonelaw Mathematics Department Green Course Revision Sheets Block E shs -> Core Classes Offered by Department Indicates ncaa clearinghouse Approved Core Class english shs -> Identify the prepositional phrases in the following sentences. Write them on a separate piece of paper shs -> Smart Phone Class Security and Safety shs -> Bordon Luciano shs -> 1 Week before Scheduled Contact shs -> Informative Research Essay Assignment shs -> 10th Daily “Fix It” Sentences shs -> The story of Perseus as told by Diodorus Download 11.38 Mb. Share with your friends:
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