Poiseuille's Law: The Volume Flow Rate Of A Pipe System

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The volume flow rate of a fluid is the amount of fluid that passes a point per second. It is dependent on a number of variables. These variables include the dimensions of the object that the fluid is flowing through, and the amount of force that is applied to it. The pressure that water in a pipe system is under is calculated using the following equation: P=F/A Where P is the pressure, F is the force that is being applied to the water, and A is the area that the water is in. The force in the previous equation can be calculated using Newton’s Second Law of Motion, F=ma (University of Tennessee, 2014). Mass is calculated by multiplying the object’s density by its volume. Volume is found by multiplying the object’s area of one of its sides …show more content…

A Newtonian fluid, such as water, will increase its resistance to a force by however many times that force is multiplied. This is not the case with a non-Newtonian fluid, which may produce more resistance, or it may produce less, depending on the individual fluid (Senese, 2010). Hence, Poiseuille’s Law does not apply. The aim of the experiment was to compare measured flow rates of water through a pipe system with those predicted by Poiseuille’s Law. Although Poiseuille’s Law can be used for liquids with different viscosities, only water was used. It was hypothesised that the values predicted by Poiseuille’s Law would be similar to those that were found experimentally, but not the exact same. This is because it was believed that the experimental results would have some small inaccuracies that were not feasibly avoidable. Two pipes were attached together, one with a length of slightly over 50cm and a radius of 5cm, and a pipe receptor near the bottom of the pipe. Both ends of the pipe were open, but the end nearest the receptor was securely covered with a pipe cap, as shown in Figure 1. The receptor was also open. The second pipe consisted of a thin metal pipe with a length of 1 metre, which was attached to another pipe cap, which was pierced through the middle, as shown in Figure 2. This allowed water to flow through the output …show more content…

This is because the law only takes into account the length of the pipe, and the area that produces friction, but not the surface texture i.e. the roughness of the pipe, which affects the amount of friction produced over the area. It is also possible that the flow of water in the pipe may not have been completely laminar, and therefore the possibility exists that some turbulent flow may have occurred. This would have resulted in a slower rate of flow, as in turbulent flow, the molecules flow in different directions and at different speeds. If the experiment was to be repeated, then it should be recommended that a stand be used to hold the bucket steady while it is being filled with water from the apparatus. This would allow for clearer reading of the water level while the experiment is running. Another possible improvement that could be made to the experimental design would be to have spare output pipes, as this would allow for repetition of the experiment if some results required

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