The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration...The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles.展开更多
本研究建立了适用于不同构型电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的简化气动模型,并采用增强延迟分离涡模拟方法,对不同构型eVTOL在起飞、降落、巡航和爬升等典型飞行阶段的气动特性进行了数值仿真。结...本研究建立了适用于不同构型电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的简化气动模型,并采用增强延迟分离涡模拟方法,对不同构型eVTOL在起飞、降落、巡航和爬升等典型飞行阶段的气动特性进行了数值仿真。结果表明,起飞阶段复合翼构型的升阻比约为多旋翼构型的1/3,降落阶段两者相近。巡航阶段复合翼构型的升阻比相较于固定翼构型低20.52%,爬升阶段低17.14%。综合比较可知,复合翼构型在起飞阶段逊色于多旋翼构型,降落阶段略优,而在巡航和爬升阶段表现均不及固定翼构型。研究结果为eVTOL的构型方案选择与气动性能优化提供了科学参考与工程依据。展开更多
扑翼飞行器通过模仿昆虫及鸟类的扑翼运动,在低雷诺数环境下具有优异的气动效率和机动性。而扑旋翼飞行器在扑翼运动的基础上实现了机翼的被动旋转运动,具备更好的悬停及垂直起降能力,是近些年新兴的研究热点。本文系统综述了扑翼微型...扑翼飞行器通过模仿昆虫及鸟类的扑翼运动,在低雷诺数环境下具有优异的气动效率和机动性。而扑旋翼飞行器在扑翼运动的基础上实现了机翼的被动旋转运动,具备更好的悬停及垂直起降能力,是近些年新兴的研究热点。本文系统综述了扑翼微型飞行器(Flapping‑wing micro air vehicles,FWMAVs)及扑旋翼微型飞行器(Flapping‑wing rotor micro air vehicles,FWRMAVs)在系统建模与控制方法方面近几年的研究进展,分析了仿昆虫扑翼飞行机理中的非定常空气动力学理论,并探讨了已有的基于仿昆虫的FWMAVs及FWRMAVs系统建模及控制方法。最后,提出了目前FWMAVs在飞行动力学和控制方法上面临的柔性翼气动力建模和非定常扰动抑制等问题,分析了FWRMAVs缺乏对其飞行动力学特性和主动姿态控制等方面研究的问题,同时本文对该领域未来进一步的研究做出了展望。展开更多
基金supported by the National Key Laboratory of Helicopter Aeromechanics Fund(No.2024-CXPT-GF-JJ-093-05).
文摘The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles.
文摘本研究建立了适用于不同构型电动垂直起降(electric vertical take-off and landing,eVTOL)飞行器的简化气动模型,并采用增强延迟分离涡模拟方法,对不同构型eVTOL在起飞、降落、巡航和爬升等典型飞行阶段的气动特性进行了数值仿真。结果表明,起飞阶段复合翼构型的升阻比约为多旋翼构型的1/3,降落阶段两者相近。巡航阶段复合翼构型的升阻比相较于固定翼构型低20.52%,爬升阶段低17.14%。综合比较可知,复合翼构型在起飞阶段逊色于多旋翼构型,降落阶段略优,而在巡航和爬升阶段表现均不及固定翼构型。研究结果为eVTOL的构型方案选择与气动性能优化提供了科学参考与工程依据。
文摘扑翼飞行器通过模仿昆虫及鸟类的扑翼运动,在低雷诺数环境下具有优异的气动效率和机动性。而扑旋翼飞行器在扑翼运动的基础上实现了机翼的被动旋转运动,具备更好的悬停及垂直起降能力,是近些年新兴的研究热点。本文系统综述了扑翼微型飞行器(Flapping‑wing micro air vehicles,FWMAVs)及扑旋翼微型飞行器(Flapping‑wing rotor micro air vehicles,FWRMAVs)在系统建模与控制方法方面近几年的研究进展,分析了仿昆虫扑翼飞行机理中的非定常空气动力学理论,并探讨了已有的基于仿昆虫的FWMAVs及FWRMAVs系统建模及控制方法。最后,提出了目前FWMAVs在飞行动力学和控制方法上面临的柔性翼气动力建模和非定常扰动抑制等问题,分析了FWRMAVs缺乏对其飞行动力学特性和主动姿态控制等方面研究的问题,同时本文对该领域未来进一步的研究做出了展望。
