Sports engineering : comparison of blade designs in traditional paddle sports

• Main Author: Mohd Faizal Selamat.
• Other Authors: Alastair Campbell Ritchie
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Mechanical engineering::Mechanics and dynamics
• Online Access: http://hdl.handle.net/10356/17137
• Institution: Nanyang Technological University

The objective of conducting this study is to analyze the effect of blade geometry on the rowing efficiency for paddles used in both traditional and popular paddling sports. This was achieved through a deep understanding of how a paddle works and applying the concepts of fluid dynamics, particularly in the fields of drag and pressure. The author selected a Macon paddle, which incorporates a design derived by technological means, and compared it against the dragon boat and Royal Thai Barge paddles, which represented the traditional boating equipment. A rectangular paddle blade was added to further enhance the study. The author adopted a two-pronged approach to the study. The first component was a computational fluid dynamics study using two commercial programs. GAMBIT was used to model the paddle in a water tank and to define the experiment’s parameters, while FLUENT acted as the solver that ran the simulation and produced the relevant results. The author opted to operate at laminar flow conditions with an initial fluid velocity of 0.5 m/s. The second aspect of the study involved a water tunnel experiment, using a 3-component balance system, in which scaled models of the four paddles, in the scale of 1:4, were placed perpendicularly to the flow to determine the drag force. The author elected to operate at four different speeds (0.1 m/s, 0.18 m/s, 0.28 m/s and 0.37 m/s) and conducted five runs for each paddle blade. The water tunnel tests were conducted to validate the findings from the CFD simulation. The computational fluid dynamics simulations proved that the Macon paddle was the most effective paddle blade design. It had the highest drag coefficient amongst the four paddles. Subsequent calculations showed that it generated the highest drag force. The Macon paddle also yielded the largest pressure readings on its surface. More significantly, the flow profile around the paddle revealed greater turbulence, due to the formation of a swirling pool in its wake. This phenomena is absent in the other paddles, indicating the Macon paddle’s effectiveness in disrupting flow and generating drag. On the contrary, the Royal Thai Barge paddle was least efficient, while the rectangular paddle and dragon boat paddle had comparable results due to similar geometry. The water tunnel experiments showed that the rectangular blade provided the best drag force at low speeds, while the Macon was best at 0.28 m/s and the Royal Thai Barge was most effective at 0.37 m/s. The relationship between drag coefficient and Reynold’s number was also deduced, proving that the curvature of the paddles enhanced the drag coefficient values when compared against a regular flat plate. The experiments also established that the Macon generated the highest turbulent flow. Although this meant that it was likely to produce the least pressure drag due to delayed flow separation, the Macon actually produced a drag coefficient of 1.7, which is almost equal to the other paddle designs. Additionally, dimensional analysis was conducted to calculate the coefficient of drags for each paddle blade at a Reynold’s number of 2500. It was discovered that the Macon paddle produced the highest drag coefficient, while the Royal Thai Barge paddle had the least value. It can be concluded that the Macon paddle is the most effective paddle blade design, as it is capable of producing the highest drag coefficient, which is beneficial to a paddler as it reduces the work done in operating the paddle. This highlights the significance of sports engineering in developing better performing equipment in the pursuit of sporting excellence. Although the author appreciates the importance of traditional paddle blade designs in preserving culture, the author recognizes the role science and technology plays in shaping the equipment used in sports.