抄録
In late years a function and the structure of the creature called biomimetics are applied to technical development. We focused on the tuna that could swim in the water at high speed. A saw-like fin is between the tail and fins from the 2nd dorsal fin in fish like tuna. A fin of the triangle is called finlets, and there is in the back and ventral. It is thought that the finlet brings the effect that the flow behind the fish rectifies at present. Its role was inspected experimentally by visualization experiment by smoke tunnel and fluid force sensing using a made model. The experimental result by the smoke tunnel was not seen in the variation of the flow with or without finlet. In addition, in the fluid force measurement, the one when equipping finlets more than the time of non-equipment, indicated a more expensive C_D.
