Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate ...Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.展开更多
基于圆周排列的Helmholtz共振腔单元,设计并实现了一种具有低频宽禁带的声人工结构,可以在结构中心处实现二维隔声效果.针对实际模型,搭建了二维声场测量平台,进行了相应的实验研究,实验结果与有限元仿真结果符合较好.该结构在较宽的频...基于圆周排列的Helmholtz共振腔单元,设计并实现了一种具有低频宽禁带的声人工结构,可以在结构中心处实现二维隔声效果.针对实际模型,搭建了二维声场测量平台,进行了相应的实验研究,实验结果与有限元仿真结果符合较好.该结构在较宽的频带内(680—1050 Hz)可以实现较好的隔声效果,最大隔声量可达41 d B.实验中还研究了单元参数及共振状态对隔声效果的影响.隔声区的大小与共振单元的分布形式有直接关系,而良好的共振状态将对提高隔声量有一定帮助.研究结果对设计新型声防护结构具有理论与应用价值.展开更多
In recent years the experiments of CERN-UA5 and NA22 Collaboration find that rapidity η-multiplicity N correlation is a visual scaling (s<sup>1/2</sup>=22—900 G-eV) and η<sub>cut</sub><su...In recent years the experiments of CERN-UA5 and NA22 Collaboration find that rapidity η-multiplicity N correlation is a visual scaling (s<sup>1/2</sup>=22—900 G-eV) and η<sub>cut</sub><sup>-</sup>N correlations are very complicated. These correlations may be helpful for building multihadron dynamics. We shall compare these data with the theory of quantum field at short展开更多
基金supported by the National Natural Science Foundation of China (10872096)the Open Fund of State Key Laboratory of Explosion Science and Technology, Beijing University of Science and Technology (KFJJ09-13)
文摘Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.
文摘基于圆周排列的Helmholtz共振腔单元,设计并实现了一种具有低频宽禁带的声人工结构,可以在结构中心处实现二维隔声效果.针对实际模型,搭建了二维声场测量平台,进行了相应的实验研究,实验结果与有限元仿真结果符合较好.该结构在较宽的频带内(680—1050 Hz)可以实现较好的隔声效果,最大隔声量可达41 d B.实验中还研究了单元参数及共振状态对隔声效果的影响.隔声区的大小与共振单元的分布形式有直接关系,而良好的共振状态将对提高隔声量有一定帮助.研究结果对设计新型声防护结构具有理论与应用价值.
文摘In recent years the experiments of CERN-UA5 and NA22 Collaboration find that rapidity η-multiplicity N correlation is a visual scaling (s<sup>1/2</sup>=22—900 G-eV) and η<sub>cut</sub><sup>-</sup>N correlations are very complicated. These correlations may be helpful for building multihadron dynamics. We shall compare these data with the theory of quantum field at short
