A self-adaptive-grid method is applied to numerical simulation of the evolu- tion of aircraft wake vortex with the large eddy simulation （LES）. The Idaho Falls （IDF） measurement of run 9 case is simulated numerica...A self-adaptive-grid method is applied to numerical simulation of the evolu- tion of aircraft wake vortex with the large eddy simulation （LES）. The Idaho Falls （IDF） measurement of run 9 case is simulated numerically and compared with that of the field experimental data. The comparison shows that the method is reliable in the complex atmospheric environment with crosswind and ground effect. In addition, six cases with different ambient atmospheric turbulences and Brunt V^iis/il^i （BV） frequencies are com- puted with the LES. The main characteristics of vortex are appropriately simulated by the current method. The onset time of rapid decay and the descending of vortices are in agreement with the previous measurements and the numerical prediction. Also, sec-ondary structures such as baroclinic vorticity and helical structures are also simulated. Only approximately 6 million grid points are needed in computation with the present method, while the number can be as large as 34 million when using a uniform mesh with the same core resolution. The self-adaptive-grid method is proved to be practical in the numerical research of aircraft wake vortex.展开更多
A new vortex sheet model was proposed for simulating aircraft wake vortex evolution.Rather than beginning with a pair of counter-rotating cylindrical vortices as in the traditional models, a lift-drag method is used t...A new vortex sheet model was proposed for simulating aircraft wake vortex evolution.Rather than beginning with a pair of counter-rotating cylindrical vortices as in the traditional models, a lift-drag method is used to initialize a vortex sheet so that the roll-up phase is taken into account. The results of this model report a better approximation to a real situation when compared to the measurement data. The roll-up induced structures are proved to influence the far-field decay.On one hand, they lead to an early decay in the diffusion phase. On the other hand, the growth of linear instability such as elliptical instability is suppressed, resulting in a slower decay in the rapid decay phase. This work provides a simple and practicable model for simulating wake vortex evolution, which combines the roll-up process and the far-field phase in simulation. It is also proved that the roll-up phase should not be ignored when simulating the far-field evolution of an aircraft wake vortex pair, which indicates the necessity of this new model.展开更多
随着空中交通流量的增长,尾流间隔精细化、动态化缩减成为民航发展的一种趋势,研究尾流演化过程也成为民航领域关注的前沿科学问题。基于此,采用雷诺平均N-S方程方法研究了B737-800飞机有无融合式翼梢小翼对飞机尾涡的演化过程影响。利...随着空中交通流量的增长,尾流间隔精细化、动态化缩减成为民航发展的一种趋势,研究尾流演化过程也成为民航领域关注的前沿科学问题。基于此,采用雷诺平均N-S方程方法研究了B737-800飞机有无融合式翼梢小翼对飞机尾涡的演化过程影响。利用美国国家航空航天局(National Aeronautics and Space Administration,NASA)动态尾流系统中尾涡消散模型(aircraft vortex spacing system prediction algorithm,APA)计算了不同气象环境参数下有无小翼的尾涡环量变化。结果表明:融合式翼梢小翼可以分割翼尖涡,有效改变翼尖气流的流动特性,增大速度梯度,减小尾涡速度、尾涡能量集中程度和尾涡强度;不同大气湍流耗散率和大气层结稳定度下,小翼对尾涡强度的减小量不同。展开更多
基金Project supported by the Boeing-COMAC Aviation Energy Conservation and Emissions Reduction Technology Center(AECER)
文摘A self-adaptive-grid method is applied to numerical simulation of the evolu- tion of aircraft wake vortex with the large eddy simulation （LES）. The Idaho Falls （IDF） measurement of run 9 case is simulated numerically and compared with that of the field experimental data. The comparison shows that the method is reliable in the complex atmospheric environment with crosswind and ground effect. In addition, six cases with different ambient atmospheric turbulences and Brunt V^iis/il^i （BV） frequencies are com- puted with the LES. The main characteristics of vortex are appropriately simulated by the current method. The onset time of rapid decay and the descending of vortices are in agreement with the previous measurements and the numerical prediction. Also, sec-ondary structures such as baroclinic vorticity and helical structures are also simulated. Only approximately 6 million grid points are needed in computation with the present method, while the number can be as large as 34 million when using a uniform mesh with the same core resolution. The self-adaptive-grid method is proved to be practical in the numerical research of aircraft wake vortex.
基金supported by the Boeing-COMAC Aviation Energy Conservation and Emissions Reduction Technology Center (AECER)
文摘A new vortex sheet model was proposed for simulating aircraft wake vortex evolution.Rather than beginning with a pair of counter-rotating cylindrical vortices as in the traditional models, a lift-drag method is used to initialize a vortex sheet so that the roll-up phase is taken into account. The results of this model report a better approximation to a real situation when compared to the measurement data. The roll-up induced structures are proved to influence the far-field decay.On one hand, they lead to an early decay in the diffusion phase. On the other hand, the growth of linear instability such as elliptical instability is suppressed, resulting in a slower decay in the rapid decay phase. This work provides a simple and practicable model for simulating wake vortex evolution, which combines the roll-up process and the far-field phase in simulation. It is also proved that the roll-up phase should not be ignored when simulating the far-field evolution of an aircraft wake vortex pair, which indicates the necessity of this new model.
文摘随着空中交通流量的增长,尾流间隔精细化、动态化缩减成为民航发展的一种趋势,研究尾流演化过程也成为民航领域关注的前沿科学问题。基于此,采用雷诺平均N-S方程方法研究了B737-800飞机有无融合式翼梢小翼对飞机尾涡的演化过程影响。利用美国国家航空航天局(National Aeronautics and Space Administration,NASA)动态尾流系统中尾涡消散模型(aircraft vortex spacing system prediction algorithm,APA)计算了不同气象环境参数下有无小翼的尾涡环量变化。结果表明:融合式翼梢小翼可以分割翼尖涡,有效改变翼尖气流的流动特性,增大速度梯度,减小尾涡速度、尾涡能量集中程度和尾涡强度;不同大气湍流耗散率和大气层结稳定度下,小翼对尾涡强度的减小量不同。
