CAJ | 학술논문

用三维非定常面元法研究了不同展弦比矩形平板拍动的非定常气动响应.通过对矩形平板沉浮和俯仰2种基元运动的三维效应分析,得到如下结论:矩形平板非定常运动中,附加惯性效应影响了升力的瞬时值,其幅值随着展弦比的降低而减小,但时均值总为零;尾缘涡和侧缘涡作用是平均升力的来源,因矩形板在一个拍动周期内流向涡的方向发生改变,涡致升力的三维效应会随拍动非定常性增强而减弱.
용삼유비정상면원법연구료불동전현비구형평판박동적비정상기동향응.통과대구형평판침부화부앙2충기원운동적삼유효응분석,득도여하결론:구형평판비정상운동중,부가관성효응영향료승력적순시치,기폭치수착전현비적강저이감소,단시균치총위령;미연와화측연와작용시평균승력적래원,인구형판재일개박동주기내류향와적방향발생개변,와치승력적삼유효응회수박동비정상성증강이감약.
Aerodynamic responses of rectangular plates with different aspect ratios during flapping motion were simulated using a three dimensional unsteady panel code. The three-dimensional effects during plunging and pitching motions were then analyzed. The results demonstrated that the added mass only contributes to the instaneous lift force. The amplitudes of lift forces induced by added mass effects would decrease with a decreasing aspect ratio, but the time-averaged contributions were always zero. Vortices shedding from trailing and side edges of rectangular plates are sources of time-averaged lift forces. As the signature of streamwise vortices would change during one flapping cycle, the three-dimensional effects on vortex-induced lift forces would reduce as the flow unsteadiness increased.