Fluid Mechanics of Swimming Propulsion 



Wu, T.Y. (1961) J. Fluid Mech. 10, 321-344 



Wu, T.Y. (1962) Accelerated swimming of a waving plate, Proc. Fourth Symp. 

 on Naval Hydrodynamics, 457-473, ONR/ACR- 92, Washington, D.C. 



Wu, T.Y. (1966) The mechanics of swimming, in "Biomechanics" (edited by 

 Y.C. Fung) Proc. Symp. on Biomechanics, Amer. Soc. Mech. Engr., New 

 York, New York 



DISCUSSION 



J. D. van Manen 



Netherlands Ship Model Basin 



Wageningen, Netherlands 



At the request of Professor Wu, I give in this discussion some results of 

 tests which were performed at the Netherlands Ship Model Basin with Dutch 

 swimmers. 



With a resistance dynamometer on the towing carriage, we have determined 

 the resistance of the towed body of swimmers. During the tests the swimmer 

 kept his hands on a bar of the resistance dynamometer just above the water. 

 The resistance curve of a swimmer is given in Fig. Dl. 



The circumstances for the second type of tests were identical to those for 

 the resistance tests; however, the swimmer was now swimming with his legs 

 only. With the resistance dynamometer, the total force developed by the swim- 

 mer (that is resistance and the leg thrust) corresponding with a certain type of 

 stroke (breast, dolphine, or crawl stroke) was measured over a large speed 

 range. The results of these tests are also presented in Fig. Dl. 



Finally, the free-running speed of the swimmer with arms and legs moving 

 was determined for the different types of strokes. An intersection between 

 these speeds and the resistance- and leg-thrust curves is made in Fig. Dl. 



For the breast stroke, it was amazing to conclude that the legs were practi- 

 cally doing nothing. For dolphine and crawl strokes, the contribution by the 

 legs to propel the body is much more favorable. Up till now, these tests have 

 been carried out with only two persons, so the results of these tests must be 

 considered with caution. More tests must be carried out before final conclu- 

 sions can be drawn. 



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