Abstract
Moving body produces the dynamic lift from the vortex rings over the body and in wake field. However, it is not clarified how long we should evaluate the vortex ring in wake filed when we estimate the dynamic lift. The purpose of the present study is to examine evaluation method of the vortex ring in wake filed to estimate the dynamic lift produced by butterfly. Therefore, it is clarified that the influence of the vortex ring emitted in wake field during before prior motion on the dynamic lift is small. Consequently, it is possible to estimate the dynamic lift using vortex ring emitted in wake filed during prior motion.
