50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition
JAN 09-12, 2012
Nashville, TN, United states
A span-wise flexible wing undergoing a rapid pitch-up and pitch-down maneuver in a steady free stream is studied with a lattice Boltzmann flexible particle method (LBFPM) in a three-dimensional space at a chord based Reynolds number of 100. The pitching rates and flexibility are systematically varied, and their effects on the generated aerodynamic forces and power efficiency are explored. It is found that at a higher pitch rate average lift coefficient increases first, as flexural rigidity decreases, and arrives at a maximum, then falls down as the flexural rigidity continuously decreases, while at a lower pitch rate, no similar phenomena is observed. It seems that flexibility can be utilized to improve lift at a high reduced frequency. A small deformation at a level of 5% due to flexibility can largely improve lift force only during pitch-down time period. On the Contrary, flexibility has a negative impact on the lift during pitch-up time period. Most likely, deformation may passively and dynamically adjust the trailing edge position along the span direction, induce larger leading edge vortices (LEV) and tip edge vortices (TEV), and enhance trailing vortex shedding due to Kutta condition, thus improve lift.
Qi DW,He GW,Liu YM. Lattice Boltzmann Simulations of a pitch-up and pitch-down maneuver of a span-wise flexible wing in a free stream flow Read More: http://arc.aiaa.org/doi/abs/10.2514/6.2012-300[C]50TH AIAA AEROSPACE SCIENCES MEETING INCLUDING THE NEW HORIZONS FORUM AND AEROSPACE EXPOSITION,2012:AIAA 2012-0300.