Discussion
In our hypothesis, we stated: If a paddle wheel and a bucketed wheel (Knight Wheel) with an improved design are subjected to identical water flow and peak voltage is recorded, then the bucketed wheel with an improved design will produce more voltage. This was proven correct as the paddle wheel generated an average of 2.88mv at peak voltage per trial, while the bucketed wheel with an improved design generated an average of 3.79mv at peak voltage per trial (see fig. b). As the paddle wheel generated much unnecessary drag while entering and exiting the water and in the design of the bucketed wheel reducing drag was a goal, the result was expected.
To test our hypothesis, we built an apparatus that would allow for controlled testing of the two wheels. It consisted of a channel of PVC pipe that had a width of 4’’ and a depth of 2’’between two buckets, one with the water to flow down the channel, the other to collect it. The bucket initially holding the water was placed at a certain height that remained consistent throughout the testing process as to control the angle of the channel. Approximately two-thirds the distance down the pipe, two pieces of plywood were fastened with wing nuts to the pipe. A 3/8’’ hole ran through each of them to allow for the support of the water wheels. These pieces of plywood could be adjusted to control the distance between the wheel and the pipe (we used a distance of 0.5cm). As the height of the buckets, angle of the channel, and the amount of water to flow down the channel was consistent, the water speed was controlled. An identical setup was used to attach the generator to the wheel and to the multi-meter so that faulty connections would not hamper the potential of each wheel.
All peak voltages from both wheels fell within 2.62 mv and 4.25 mv (see table 1). The bucketed wheel outperformed the paddle wheel with an average peak voltage of 3.79 mv. The paddle wheel had an average peak voltage of 2.88 mv (see fig. b). The bucketed wheel’s results fell between 3.22 mv and 4.25 mv, often (7/10 times) falling between 3.84 mv and 4.25 mv. The paddle wheel’s results fell between 2.62 mv and 3.30 mv, more often (8/10 times) falling between 2.62 mv and 3.00 mv (see fig. a). The fact that the improved bucketed wheel outperformed the paddle wheel is likely due to form drag and induced drag. Induced drag occurs when a fluid curls around the top of a wing, or the paddles and buckets of the water wheel. The fluid curling around the top creates a vortex. The steeper the angle of attack, the more drag is produced. The paddle wheel had a 90-degree angle of attack while the bucketed wheel had a 20-degree angle of attack. This significant difference in angles most likely contributed to the results. Form drag is caused by fluid flowing over a shape. A flat plate (paddles on the paddle wheel) will produce more drag than a triangle (buckets on our improved design). These principles are likely what affected the results.
This experiment was a valid way of testing the innovation. All major variables were controlled and the results were consistent. A possible source of error may have been that the aluminum on the paddle wheel would bend in the direction of the water flow. In an effort to control this, they were straightened before every trial. If this project was repeated, a sturdier metal may make a small difference. Also, overshooting and breast shooting them could test different functions of the waterwheels.
To test our hypothesis, we built an apparatus that would allow for controlled testing of the two wheels. It consisted of a channel of PVC pipe that had a width of 4’’ and a depth of 2’’between two buckets, one with the water to flow down the channel, the other to collect it. The bucket initially holding the water was placed at a certain height that remained consistent throughout the testing process as to control the angle of the channel. Approximately two-thirds the distance down the pipe, two pieces of plywood were fastened with wing nuts to the pipe. A 3/8’’ hole ran through each of them to allow for the support of the water wheels. These pieces of plywood could be adjusted to control the distance between the wheel and the pipe (we used a distance of 0.5cm). As the height of the buckets, angle of the channel, and the amount of water to flow down the channel was consistent, the water speed was controlled. An identical setup was used to attach the generator to the wheel and to the multi-meter so that faulty connections would not hamper the potential of each wheel.
All peak voltages from both wheels fell within 2.62 mv and 4.25 mv (see table 1). The bucketed wheel outperformed the paddle wheel with an average peak voltage of 3.79 mv. The paddle wheel had an average peak voltage of 2.88 mv (see fig. b). The bucketed wheel’s results fell between 3.22 mv and 4.25 mv, often (7/10 times) falling between 3.84 mv and 4.25 mv. The paddle wheel’s results fell between 2.62 mv and 3.30 mv, more often (8/10 times) falling between 2.62 mv and 3.00 mv (see fig. a). The fact that the improved bucketed wheel outperformed the paddle wheel is likely due to form drag and induced drag. Induced drag occurs when a fluid curls around the top of a wing, or the paddles and buckets of the water wheel. The fluid curling around the top creates a vortex. The steeper the angle of attack, the more drag is produced. The paddle wheel had a 90-degree angle of attack while the bucketed wheel had a 20-degree angle of attack. This significant difference in angles most likely contributed to the results. Form drag is caused by fluid flowing over a shape. A flat plate (paddles on the paddle wheel) will produce more drag than a triangle (buckets on our improved design). These principles are likely what affected the results.
This experiment was a valid way of testing the innovation. All major variables were controlled and the results were consistent. A possible source of error may have been that the aluminum on the paddle wheel would bend in the direction of the water flow. In an effort to control this, they were straightened before every trial. If this project was repeated, a sturdier metal may make a small difference. Also, overshooting and breast shooting them could test different functions of the waterwheels.