Multi-structure with movement of bird and surrounding air

　　There is various size of time with movement of bird and surrounding air.

　　　�@　Time larger than beating period
　　　　　　continuous beating-, intermittent beating-，gliding-, diving-, takeoff-,
　　　　　　landing-flight, etc.

　　　�A　Time comparative with beating period
　　　　　　extension-contraction of joints in writ･elbow･shoulder, temporal change
　　　　　　of chord･angle of attack･curve which may be different toward span
　　　　　　direction, folding-spreading of wing, separation of feathers with slit, etc.

　 　　�B　Time smaller than beating period
　　　　　　appearance-disappearance of lift or drag (circulation or wake), etc.

　　The mechanical action and effect with the movement in smaller time
　should be accumulated and averaged, and they should appear in the action
　and effect at larger time.

　　For small sized bird, �B approaches to �A, then the mechanical action
　and effect are complicated.

　　The beating flight looks like the airplane at time of �@, but it is different
　entirely at time of �A or �B.
　(This is characteristic of multi-structural phenomenon.)

　　The visible flying pose is restricted with respect to the size of time.
　The flying pose that looks at short time (snapshot, pictre, sculpture) is
　different from that looks at long time (TV, video，movie).

　　The flying bird and the surrounding air possess multi-structure with
　respect to the length, too and it should make up solid-formative beauty
　（form and color) that is proper to birds.

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