Forces, fluid dynamics, rowing
Holding the blade through slowly
Cavitation and turbulence makes a stroke less efficient, disrupting the transfer of force that a rower applies to the water, therefore reducing the effectiveness of the blade propulsion. As mentioned previously, if the blade is moved too fast through the water, water pressure surrounding the blade drops, forming vapour bubbles, only in cold enough waters. When the blade moves too fast through the water, shearing can occur. Shear stress is generated when layers slide past each other at varying speeds, as when cards in a deck of cards slide against each other, with differing velocities. Something similar occurs with blades in the water. To generate propulsion, the blade needs to displace the largest possible volume of water in the opposite direction. Therefore, this shearing reduces the propulsion since water is slipping past the blade and not being pushed in the other direction, so there is little drag on the spoon, and the transfer of power from the rower is extremely inefficient. Another reason is due to Hill’s Principle. When the blade moves too fast through the water, this is because the legs of the rower have been pressed down too fast, which can also have adverse effects on the amount of power exerted by the rower. Hill’s principle is the relation between force and velocity, meaning the slower the legs are pressed down, the larger the force exerted. There is therefore a compromise between speed and power per stroke. By effectively connecting at the catch, and holding the blade long and slower through the water, this can ensure the spoon is fully connected , and most efficiently transferring the rowers power to the water, therefore making the boat travel through the water the fastest, without pushing harder or faster.
Conclusion
Moving a rowing boat fast comes down to a rower’s efficiency and choices based on their personal technique. By using telemetry analysis, and combining it with effective coaching, a rower can analyse their weaknesses, and row a longer, more efficient stroke. Combining this with an effective choice of blade design can allow for a rower to reach their maximum potential on the water.
Bibliography
https://en.wikipedia.org/wiki/Rowing_(sport). Accessed: 18/07/2024 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6593051/#:~:text=This%20force%2Dvelocity%20(F%2 DV),contraction%20(Huxley%2C%201957). Accessed: 25/08/24 https://pure.tudelft.nl/ws/portalfiles/portal/82497694/17082020_dissertation.pdf 25/08/24 https://www.concept2.com/oars/sweeps/blades. Accessed: 25/08/24 https://www.concept2.co.uk/oars/oar-options/blades/color-options. Accessed: 25/08/24 https://biorow.com/index.php?route=information/news/news&news_id=67. Accessed: 25/08/24 History (gvsu.edu). Accessed: 25/08/24 Talking forces: thrust vs drag. Accessed: 25/08/24 http://hyperphysics.phy-astr.gsu.edu/hbase/Fluids/kutta.html. Accessed: 25/08/24 https://en.m.wikipedia.org/wiki/Kutta_condition. Accessed: 25/08/24 https://eodg.atm.ox.ac.uk/user/dudhia/rowing/physics/basics.html. Accessed: 25/08/24 https://en.wikipedia.org/wiki/Kilogram-force. Accessed: 25/08/24
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