Affiliations: Department of Aeronautical Science and Flight
Operation, Hankuk Aviation University, 200-1 Hwajeon-dong, Deogyang-gu, Goyang
city, Kyeonggi-do, 412-791, Korea | Department of Aerospace Engineering, Korea Air Force
Academy, Ssangsuri, Namil-myun, Chungwon-gun, Chungbuk-do, 363-849, Korea.
E-mail: myongsohn@hanmail.net
Abstract: A flow visualization of the two-dimensional rigid fling-clap motions
of the flat-plate wing is performed to get the knowledge of fling-clapping
mechanism that might be employed by insects during flight. In this numerical
visualization, the time-dependent Navier-Stokes equations are solved for two
types of wing motion; 'fling followed by clap and pause
motion' and 'cyclic fling-clapping motion'.
The result is observed regarding the main flow features such as the sequential
development of the two families of separation vortex pairs and their movement.
For the 'fling followed by clap and pause motion', a
strong separation vortex pair of counterrotation develops in the opening
between the wings in the fling phase and they then move out from the opening in
the following clap phase. For 'the cyclic fling-clapping
motion', the separation vortex pair developed in the outside space
in the clap phase move into the opening in the following fling phase. The
separation vortex pair in the opening developed in the fling phase of the
cyclic motion is observed to be stronger than those of the 'fling
followed by clap and pause motion'. Regarding the strong fling
separation vortex and the weak clap separation vortex above it in the opening,
the flow pattern of the fling phase of the cyclic fling and clap motion is
different to that of the fling phase of the first cycle. The flow pattern of
the third cycle of the cyclic fling-clapping motion is observed to be almost
same as that of the second cycle. Therefore, a periodicity of the flow pattern
is established after the second cycle.
