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Today I bring you a study on rowing efficiency from French scientists. Scientists have developed a 10:1 size rowing robot and analyzed in detail the impact of various rowing methods on efficiency.
This work comes from the LedHyX laboratory in France, and the experimental results were published in Physics Today in June this year.
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RowBot
The picture below is from the Olympic rowing competition. Athletes row at the same time, then lift the paddle at the same time, reset the body, put the paddle into the water, and paddle at the same time, and so on.
During this process, the racing boat is constantly accelerating, sliding, and decelerating. When the speed is constantly fluctuating, it will receive more friction from the water flow, which means that this energy is wasted.
So, in order to figure out how to row a boat in the most efficient way, researchers built a small robot called RowBot . The small robot is made of 2m long fiberglass hull and houses eight pairs of Arduino -controlled paddles to simulate the movement of a rowing boat. The Arduino can control the paddle to glide in different modes.
The researchers found that the acceleration and deceleration of the hull during synchronized paddling caused a 20 percent change in the speed of the boat, and this change caused the hull to experience 5 percent more friction. This is the 5% that decides the outcome!
Experiments show that the speed of the boat is the most stable when paddling asynchronously (each paddle is 45 degrees out of phase, imagine the wave of people at the concert~~), just like the green line in the picture below.
Asynchronous row
But to the researchers' surprise, the average efficiency of synchronized paddles was higher ( dashed blue line ). What about the 5% added friction ?
Research must be done. Once again, the researchers thoroughly analyzed all the details of the rowing, and finally found that the body of the rower , which was ignored in the research hypothesis, is dynamic . (Doing research, the premise of assumptions is very important~~)
The thing is actually like this, when rowing, the athletes paddle together, close the paddle after a row, and then move the body synchronously to reset, ready for the next row. (The boat of friendship, rowing together is fast)
The key is that in the process of moving the body this time, the overall reaction is given to the boat, so that the boat can also be accelerated by inertia when the athlete is not paddlingAsynchronous rowing, on the other hand, produces no acceleration (which is offset by the individual movements of the individual crew members).
This story tells us that when people gather firewood, the flame is high, and they row the boat together ~~