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采用数值模拟方法研究了蜻蜓双翼做间歇性拍动运动时的气动特征。计算结果表明,在所研究的雷诺数工况下(Re=157),模型翼的平均升力系数和平均推力系数随着间歇占比的增大而减小,前段下降较快,中段下降平缓,后段下降至零。其中平均推力系数受到的影响相对平均升力系数更大,当连续飞行转变为间歇性飞行时,短暂滑翔初期和短暂滑翔稳定阶段均大幅削弱推力系数,共占42.7%;而对于升力系数,短暂滑翔稳定期对升力系数的削弱作用很大,占41.4%,但短暂滑翔初期却对平均升力系数的提高贡献8%。间歇拍动飞行能够提高蜻蜓飞行的升推比,当滑翔时长占间歇飞行周期之比为0.3时,平均升推比接近为1。
The aerodynamic characteristics of the dragonfly wings during intermittent flapping motion were studied by numerical simulation method. The calculated results show that under the Reynolds number conditions (Re = 157), the average lift coefficient and the average thrust coefficient of the model wing decreases with the increase of the intermittent proportion, the former decreases rapidly and the middle decreases gently, After the paragraph dropped to zero. The average thrust coefficient is affected by the relative average lift coefficient is larger, when the continuous flight into intermittent flight, both short-gliding and short gliding stability stage significantly weakened thrust coefficient, a total of 42.7%; and for the lift coefficient, a brief glide The stabilizing period played a great role in weakening the lift coefficient, accounting for 41.4% of the total, but contributed 8% to the average lift coefficient during the initial short-term gliding. Intermittent flapping flight can increase the ascending thrust ratio of dragonfly flight. When the gliding duration takes up 0.3 at intermittent flight cycle, the average uplift ratio is close to 1.