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Reflection Report:Group 8: Stephanie Luo, Karla Vincent, Cooper WarrenTutor:Alison HaireDesign exercise: University of Wollongong, 5/1/2018 3. Statement of purposeThe general purpose of this investigation was to design a tank which would be best suited to the given apparatus, with the goal of hitting the micro hydro turbine (water wheel), using the water projected from the orifice. This experiment reflects on some real-world issues and highlights how the combination of collaboration and scientific knowledge in such a scenario may be all that is necessary to solve and in specific cases even benefit from the problem.The investigation brings individuals who are capable of resolving intricate problems together to face a challenging scenario. Each individual in this experiment is intellectually skilful, and together they should be able to use their combined knowledge to present a practical solution to the problem.It is highly likely that the members of the group are strangers, this fact tests the individuals on their ability to respond to such a “challenge” with two likely outcomes. The group will either work efficiently and effectively, or with conflict.4. Results of brainstorming and rationale for chosen concept Cone shaped tank would create the most controlled water flow and would assist in the extraction of waterExternal cylindrical shape would help hold the plastic bags shape (as it hangs over the edge of the cylinder) so there would be no residue water trapped at the bottom Height of cylinder (30 cm) had to be shorter than height of plastic bag (32cm) for the bag to overhang Proposed tank design 123Diagram and notes*first basic design idea-quickly changed due to unsupportive base*second design idea-incorporated into third design supporting ‘wall’*dismissed due to inadequacy to hold bag in desired position *third and final design *incorporated previous two design ideas *cylinder acted as supporting exterior whilst internal cone structure controlled shape of plastic bag 5. Brief description of tank and drawings with dimensions Brief description of tank, drawings and calculations                                                                             Our tank design consisted of two parts, a cylinder with two hollow ends and a cone with the same radius as the cylinder so it would fit inside. The cylinder had a height of 30cm and a radius of 4cm. The cone had a height of 12 cm and a radius of 4cm for the hollow end facing upwards and a radius of roughly 2.1cm for the hollow section facing down, which was to later be connected to the discharge system.Principle behind design                                                                                                    We believed that by combining the structure of a cone and cylinder together we would create a more successful tank design as the cone would shape the plastic bag into the desired structure for maximum extraction of water and the cylindrical exterior would a. Hold the bag so there wouldn’t be any residue water trapped in any overlapping layers of the bag and b. Provide a strong external wall to hold the design upright. The cone on the inside of the cylinder was constructed to connect to the discharge system and aid in the balancing of the tank. Fundamentally, we fabricated our tank to primarily achieve the maximum height of the mass but also stability so it would be able to stand upright and reduce the rate of loss of water through unnecessary movement.                                                                                                                                   6. ResultsOur tank: GroupOrifice chosen (mm)Max height of mass (mm)Max distance (mm)85250900Our group results were successful. We achieved a sufficient water flow which reached a distance of 900mm and hit the water wheel at a distance of 600mm. The weight connected to the wheel reached a height of 250mm. The flow of water was strong and our tank allowed for a sufficient amount of pressure to achieve this flow. Peers tanks:GroupTank ProfileTank cross-section sketchWall surface area (mm2)Tank height (mm)11257302702 62125304327488.91254 n/a10698290538013.272206 7195215742411.5291Peers results: GroupOrifice chosen (mm)Max height of mass (mm)Max distance (mm)152508002530850310010045256505102010306520093075601200It can be seen from the table that groups who chose the 5mm orifice achieved better results than those who chose the 10mm orifice. Furthermore groups with a cone shaped tank design performed better (groups 1 and 6) than those using a more cylindrical design. Group 3 did not move the mass on the water wheel as their water didn’t reach the wheel itself. Groups 2, 4, 5 and 7 did not raise the mass to a sufficient height as the water either overshot or didn’t have enough pressure resulting from their tank design. 7. ReflectionReflection of our group’s performanceOur group worked cohesively to discuss and design the best tank we could. Before settling on a design we drew diagrams of possible tanks, discussed what shapes to use and the dimensions that would be best. The final design came from a mixture of each others ideas resulting in a unanimous decision. We worked well together as a team and this showed in our results.During the fabrication of our tank, there were not any parts that were very fiddly. To make the cone, we simple rolled up cardboard and sticky taped it and the cylinder was much the same process. This easy process benefited us as it gave us more time to make calculations and predict the best orifice. Furthermore, when writing our assessment report, we allocated roles and assigned equal parts successfully. Throughout the assignment we had meetings and checkups to report progress and kept a constant discussion through Facebook. This allowed us to work together and combine ideas. One issue that did occur was that during the design of the tank, we believed that the tank would sit in the opening of the discharge system. This gave it a minimum diameter of 20mm. However when we attempted to begin testing we realised that the minimum diameter must be greater than 40mm as it is required to sit above the discharge system. This greatly affected our result as we had to cut the cone to the required diameter losing 40mm off the height of the cone. Even though our tank still performed well, this extra height of the cone would have provided more water pressure, possibly increasing the height of the mass. Furthermore, this changed the water height in our tank, making it much lower than before. This left 100mm of wasted cardboard. As we are given a set amount of cardboard (stated in section 5), it would be beneficial to take advantage of all of our resources. This can be improved on in the next tank.  Reflection of ResultsOverall our tank performed with success. The height the mass connected to the water wheel reflects that our stream of water was able to hit the wheel with a substantial amount of force. This force is kinetic energy (KE), created by the potential energy (PE) of the water in the tank. The funnel shape of our tank allowed for the transformation of PE to KE to occur without a substantial amount of lost energy. The plastic bag held the shape of our tank, allowing for an easy flow into the discharge system which assisted in the energy transfer.In another aspect, the height of our tank aided the amount of force we were able to create. Water pressure is increased by height and the height of our tank allowed for more water pressure than other designs. The water level reached 210mm which increased the water pressure by 2060P. This increased pressure resulted in higher PE which translated to higher KE.This effect was also noticeable in other group’s tanks. Groups with an increased tank height all had strong powerful water streams. Furthermore, all these groups used cone shaped tanks which assisted in this result. These groups include Group 1, 3 and 7. Although the strong forces may not show in their results, these groups did achieve a strong and successful water pressure.Groups who did not achieve higher forces were groups who used different designs such as a cylinder or a prism. The cylindrical shaped tank also didn’t hold the shape of the plastic bag. This occurred with Group 2, 3 and 4. The bag funnelled the water into the discharge system and the cone shape funnelled the water smoothly. In some tanks by using a cylinder shape, the bag drooped and some water stayed stationary beside the hole into the discharge system. Thus, the pressure created by the tank was lost in the process and became far less than that of the cone and caused less of a result.The orifice selected impacted the result of the experiment greatly. When the 10mm orifice was chosen it resulted in a quicker spout of water, shortening the time it could’ve spun the water wheel. More water was used at a quicker rate and thus caused an imprecise hit which occurred in group 3’s test. Their tank design also plays a role in this but the 5mm orifice would have provided more pressure, allowing them to possible hit the water wheel.The other group that chose the 10mm orifice was group 5 who were able to hit the water wheel but only raised it 20mm, much lower than many other groups. Again their flow of water was very imprecise, overshooting the water wheel. The quick rate of water consumption didn’t allow the water to last long enough to fully affect the wheel. By using the 5mm orifice increased the duration of the water stream thus raising the wheel to a greater height. We chose the 5mm orifice and this allowed for a strong and longer lasting stream compared to other groups. The smaller opening allowed for a precise stream to hit the water wheel for long enough, with enough force, to raise the mass to a successful height.However, some streams of water overshot the water wheel at its strongest flow, restricting the amount of force exerted. This occurred in our experiment as well as many other groups. This meant that when the stream did actually reach the wheel, it didn’t push with the greatest force possible. In comparison to other groups our stream performed relatively well, however the overexerted stream affected how much we were able to raise the mass attached to the water wheel. For Group 5 and 7, they overshot the wheel by over 400mm and this had a major effect on their results causing them to only raise the height 20mm and 60mm respectively. Further ImprovementWe were informed of Bernoulli’s Principle to calculate and describe the relationship between the pressure and velocity of the moving fluid (water), thus possible improvements to the overall calculations could be made including using Bernoulli’s equation.  By rearranging and substituting equations (equations seen below), we were assisted in concluding and understanding that the cross-sectional area of the tank did not affect the pressure exerted by the water. This understanding will allow us to remove a constraint on our design as it will not affect the results produced by our design. This allows for more time for calculations such at what height the water will reach our tank, maximum distance the water will travel and the amount of pressure exerted by the water.Understandably, the position of the center of gravity of an object affects its stability, the lower the center of gravity, the more stable it becomes and the higher the center of gravity, the more less stable it becomes. In our new design we could reduce the cone height to decrease the center of gravity and stability of the tank whilst still ensuring it produces the desired structure for the plastic bag. We will also need to compensate for the need of a 40mm diameter opening at the base of the cone, which is the minimum requirement of the tank design given in order for it to connect to the discharge system. Other possible avenues are improving the hydro system. The midpoint of the water wheel was placed at 600mm away from the opening of the tank and most groups stream of water overshot this distance. If the wheel was at a further distance, more force would be exerted onto the wheel increasing efficiency. 8. Mapping of learning outcomes Learning outcome 1 and Learning outcome 2 have been achieved through this investigation. Learning outcome 1, Draw on new knowledge to critically reflect on learning experiences: Throughout the duration of the experimental investigation, knowledge gained in the first two STEM lectures was applied. This mainly included Newton’s Laws of Motion, sustainability and using the thought process of an engineer. Drawing on this knowledge has allowed for the individuals in this group investigation to create a deeper understanding of the newly processed information. Learning outcome 2, Demonstrate effective teamwork and time management: While following the experimental method, individuals in the group were assigned to work through separate areas of the investigation. The areas were equally important, and this allowed the workload to be spread evenly between the three group members. This distribution of the workload increased the overall productivity of the group, enabling the investigation to be completed efficiently and effectively.9. Conclusions The design of our group’s tank, proved to be successful in testing, flowing at approximately the right rate to hit the micro hydro turbine (water wheel) and lift the weight to a height of 250mm off the ground. It is highly possible that this occurred due to the shape of the tank itself. As seen in the results, the tank designs with the shape of a cone incorporated (Groups 1, 6, 7, and 8) lifted the weight higher than those without or those who rendered the cone shape useless (Groups 2, 3, 4 and 5), as they were too wide where they met the apparatus. The general idea discussed by the group before proceeding to formulate our design concepts was to maximise the pressure of the system as much as physically possible to increase the force at which the water would hit the micro hydro turbine. After the successful completion of the experiment we used our knowledge of physics to conclude that this hypothesised idea provided the force necessary to lift the weight to a reasonable height. Overall, our group worked together effectively and efficiently to design and test a successful tank design. The report section of the experiment was also handled swiftly and without complaint, providing a more detailed explanation as to the purpose of the experiment, what happened throughout the experiment, how it was completed and why we all choose our design concepts. The collaborative experience proved to be extremely beneficial in such a scenario.10. References 11. AppendixConducted experiment and recorded results/observations on 5/1/18Brief meeting to delegate tasks on 9/1/18Ongoing FaceBook group discussion since 9/1/18Meeting to discuss progress of report and clarify any questions on 10/1/18Check-in meeting to confirm group progress on 11/1/18

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