This paper provides a parametric study to obtain the optimal wing rotation angle for the generation of maximum transla- tional force in an insect-mimicking Flapping-Wing Micro Air Vehicle （FWMAV） during hovering. Th...This paper provides a parametric study to obtain the optimal wing rotation angle for the generation of maximum transla- tional force in an insect-mimicking Flapping-Wing Micro Air Vehicle （FWMAV） during hovering. The blade element theory and momentum theory were combined to obtain the equation from which the translational aerodynamic force could be esti- mated. This equation was converted into a non-dimensional form, so that the effect of normalized parameters on the thrust coefficient could be analyzed. The research showed that the thrust coefficient for a given wing section depends on two factors, the rotation angle of the wing section and the ratio of the chord to the travel distance of the wing section in one flapping cycle. For each ratio that we investigated, we could arrive at an optimal rotation angle corresponding to a maximum thrust coefficient. This study may be able to provide guidance for the FWMAV design.展开更多
大型风力机的气动载荷、惯性力和弹性力等交变载荷会引起柔性风轮、塔架等构件的耦合振动,影响风力机性能和使用寿命。针对水平轴风力机的气弹耦合数学模型的建立及其数值积分方法进行研究。采用能反映弹性变形的超级单元(Super-element...大型风力机的气动载荷、惯性力和弹性力等交变载荷会引起柔性风轮、塔架等构件的耦合振动,影响风力机性能和使用寿命。针对水平轴风力机的气弹耦合数学模型的建立及其数值积分方法进行研究。采用能反映弹性变形的超级单元(Super-element,SE)将柔性构件离散为带有力元弹簧和阻尼器的旋转铰连接的有限个数的刚体。基于多体系统(Multi-body system,MBS)动力学理论和混合多体系统(Hybrid multi-body systems,HMBS)的建模方法,通过编制的仿真程序自动建立受约束的风力机多体系统动力学方程并进行数值求解。通过傅里叶谱分析方法,实现了系统动力学特性分析。算例分析美国可再生能源实验室(National renewable energy laboratory,NREL)公布的5 MW水平轴近海风力机的固有频率与振型,验证了程序的有效性和建模方法的正确性。基于叶素动量(Blade element momentum,BEM)理论,计算叶片变形状态下各刚体所受的气动力,在数值积分过程中实时实现流固之间的耦合。分析结果表明超级单元能用较少的自由度准确地描述风力机气动载荷、惯性力和弹性力三者之间的耦合。所开发的仿真程序能为风力机气弹耦合及稳定性分析和控制系统设计提供实用的分析平台。展开更多
文摘This paper provides a parametric study to obtain the optimal wing rotation angle for the generation of maximum transla- tional force in an insect-mimicking Flapping-Wing Micro Air Vehicle （FWMAV） during hovering. The blade element theory and momentum theory were combined to obtain the equation from which the translational aerodynamic force could be esti- mated. This equation was converted into a non-dimensional form, so that the effect of normalized parameters on the thrust coefficient could be analyzed. The research showed that the thrust coefficient for a given wing section depends on two factors, the rotation angle of the wing section and the ratio of the chord to the travel distance of the wing section in one flapping cycle. For each ratio that we investigated, we could arrive at an optimal rotation angle corresponding to a maximum thrust coefficient. This study may be able to provide guidance for the FWMAV design.
文摘大型风力机的气动载荷、惯性力和弹性力等交变载荷会引起柔性风轮、塔架等构件的耦合振动,影响风力机性能和使用寿命。针对水平轴风力机的气弹耦合数学模型的建立及其数值积分方法进行研究。采用能反映弹性变形的超级单元(Super-element,SE)将柔性构件离散为带有力元弹簧和阻尼器的旋转铰连接的有限个数的刚体。基于多体系统(Multi-body system,MBS)动力学理论和混合多体系统(Hybrid multi-body systems,HMBS)的建模方法,通过编制的仿真程序自动建立受约束的风力机多体系统动力学方程并进行数值求解。通过傅里叶谱分析方法,实现了系统动力学特性分析。算例分析美国可再生能源实验室(National renewable energy laboratory,NREL)公布的5 MW水平轴近海风力机的固有频率与振型,验证了程序的有效性和建模方法的正确性。基于叶素动量(Blade element momentum,BEM)理论,计算叶片变形状态下各刚体所受的气动力,在数值积分过程中实时实现流固之间的耦合。分析结果表明超级单元能用较少的自由度准确地描述风力机气动载荷、惯性力和弹性力三者之间的耦合。所开发的仿真程序能为风力机气弹耦合及稳定性分析和控制系统设计提供实用的分析平台。
