采用流热耦合方法分别对内部冷却的超跨音直列叶栅和环形叶栅进行数值模拟。其中直列叶栅为径向圆孔内冷的NASA MARK II叶片,通过数值解与实验值的对比,验证流热耦合方法的准确性,并讨论层流、不同湍流及转捩模型在流热耦合模拟中的特...采用流热耦合方法分别对内部冷却的超跨音直列叶栅和环形叶栅进行数值模拟。其中直列叶栅为径向圆孔内冷的NASA MARK II叶片,通过数值解与实验值的对比,验证流热耦合方法的准确性,并讨论层流、不同湍流及转捩模型在流热耦合模拟中的特点。在此基础上选用考虑和不考虑转捩模型的SST湍流模型,以采用径向成形内冷通道的某高压级导叶环形叶栅为研究对象,讨论其复杂流场与换热之间的相互作用。结果表明:为准确预测流热耦合作用下的温度分布,需要选择合理的湍流模型,并考虑转捩的影响,不同热边界同样会影响气动效果如分离再附等;三维超跨音流场中激波、分离以及通道涡、角隅涡等涡系结构与温度场之间存在复杂的相互作用;内部换热对于降低叶片表面温度有着重要作用,通过数值解可指导冷却结构优化设计。展开更多
Based on a nonhydrostatic numerical ocean model developed by one of the authors, the interaction of an intemal solitary wave with a step-type topography was investigated. Over the step topography, the flow pattern cou...Based on a nonhydrostatic numerical ocean model developed by one of the authors, the interaction of an intemal solitary wave with a step-type topography was investigated. Over the step topography, the flow pattern could be classified into three categories： 1） the propagation and spatial structure of the internal solitary wave was little influenced by the bottom topography, 2） the internal solitary wave was significantly distorted by the blocking effect of the topography without the occurrence of wave breaking and 3） the internal solitary wave was broken as it encountered and passed over the bottom topography. A detailed description of the processes leading to wave breaking is given in this paper together with energy budget analysis. The results revealed that the maximum of the energy dissipation rate is no more than 40%, which is consistent with available experimental data.展开更多
The parallel computing algorithm for a nonhydrostatic model on one or multiple Graphic Processing Units （GPUs） for the simulation of internal solitary waves is presented and discussed. The computational efficiency o...The parallel computing algorithm for a nonhydrostatic model on one or multiple Graphic Processing Units （GPUs） for the simulation of internal solitary waves is presented and discussed. The computational efficiency of the GPU scheme is analyzed by a series of numerical experiments, including an ideal case and the field scale simulations, performed on the workstation and the super- computer system. The calculated results show that the speedup of the developed GPU-based parallel computing scheme, compared to the implementation on a single CPU core, increases with the number of computational grid cells, and the speedup can increase quasi- linearly with respect to the number of involved GPUs for the problem with relatively large number of grid cells within 32 GPUs.展开更多
In this study, an analysis on the internal wave generation via the gravity collapse mechanism is carried out based on the theoretical formulation and the numerical simulation. With the linear theoretical model, a rect...In this study, an analysis on the internal wave generation via the gravity collapse mechanism is carried out based on the theoretical formulation and the numerical simulation. With the linear theoretical model, a rectangle shape wave is generated and propagates back and forth in the domain, while a two-dimensional non-hydrostatic numerical model could reproduce all the observed phenomena in the laboratory experiments conducted by Chen et al. （2007）, and the related process realistically. The model results further provide more quantitative information in the whole domain, thus allowing an in depth understanding of the corresponding internal solitary wave generation and propagation. It is shown that the initial type of the internal wave is determined by the relative height between the perturbation and the environmental density interface, while the final wave type is related to the relative height of the upper and lower layers of the environmental fluid. The shape of the internal wave generated is consistent with that predicted by the KdV and EKdV theories if its amplitude is small, as the amplitude becomes larger, the performance of the EKdV becomes better after the wave adjusts itself to the ambient stratification and reaches an equilibrium state between the nonlinear and dispersion effects. The evolution of the mechanical energy is also analyzed.展开更多
文摘采用流热耦合方法分别对内部冷却的超跨音直列叶栅和环形叶栅进行数值模拟。其中直列叶栅为径向圆孔内冷的NASA MARK II叶片,通过数值解与实验值的对比,验证流热耦合方法的准确性,并讨论层流、不同湍流及转捩模型在流热耦合模拟中的特点。在此基础上选用考虑和不考虑转捩模型的SST湍流模型,以采用径向成形内冷通道的某高压级导叶环形叶栅为研究对象,讨论其复杂流场与换热之间的相互作用。结果表明:为准确预测流热耦合作用下的温度分布,需要选择合理的湍流模型,并考虑转捩的影响,不同热边界同样会影响气动效果如分离再附等;三维超跨音流场中激波、分离以及通道涡、角隅涡等涡系结构与温度场之间存在复杂的相互作用;内部换热对于降低叶片表面温度有着重要作用,通过数值解可指导冷却结构优化设计。
基金This work was financially supported by the National Natural Science Foundation of China(40576010).
文摘Based on a nonhydrostatic numerical ocean model developed by one of the authors, the interaction of an intemal solitary wave with a step-type topography was investigated. Over the step topography, the flow pattern could be classified into three categories： 1） the propagation and spatial structure of the internal solitary wave was little influenced by the bottom topography, 2） the internal solitary wave was significantly distorted by the blocking effect of the topography without the occurrence of wave breaking and 3） the internal solitary wave was broken as it encountered and passed over the bottom topography. A detailed description of the processes leading to wave breaking is given in this paper together with energy budget analysis. The results revealed that the maximum of the energy dissipation rate is no more than 40%, which is consistent with available experimental data.
基金supported by the Natural Science Foundation of Tianjin, China (Grant No. 12JCZDJC30200)the National Natural Science Foundation of China (Grant No. 51021004)the Fundamental Research Fund for the Central Nonprofit Research Institutes of China (Grant No. TKS100206)
文摘The parallel computing algorithm for a nonhydrostatic model on one or multiple Graphic Processing Units （GPUs） for the simulation of internal solitary waves is presented and discussed. The computational efficiency of the GPU scheme is analyzed by a series of numerical experiments, including an ideal case and the field scale simulations, performed on the workstation and the super- computer system. The calculated results show that the speedup of the developed GPU-based parallel computing scheme, compared to the implementation on a single CPU core, increases with the number of computational grid cells, and the speedup can increase quasi- linearly with respect to the number of involved GPUs for the problem with relatively large number of grid cells within 32 GPUs.
基金the National Natural Science Foundation of China (Grant Nos. 61072145, 41176016)the Fundfor Creative Research Groups by National Natural Science Foundation of China (Grant No. 41121064)the State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences (Grant No. LTO1104)
文摘In this study, an analysis on the internal wave generation via the gravity collapse mechanism is carried out based on the theoretical formulation and the numerical simulation. With the linear theoretical model, a rectangle shape wave is generated and propagates back and forth in the domain, while a two-dimensional non-hydrostatic numerical model could reproduce all the observed phenomena in the laboratory experiments conducted by Chen et al. （2007）, and the related process realistically. The model results further provide more quantitative information in the whole domain, thus allowing an in depth understanding of the corresponding internal solitary wave generation and propagation. It is shown that the initial type of the internal wave is determined by the relative height between the perturbation and the environmental density interface, while the final wave type is related to the relative height of the upper and lower layers of the environmental fluid. The shape of the internal wave generated is consistent with that predicted by the KdV and EKdV theories if its amplitude is small, as the amplitude becomes larger, the performance of the EKdV becomes better after the wave adjusts itself to the ambient stratification and reaches an equilibrium state between the nonlinear and dispersion effects. The evolution of the mechanical energy is also analyzed.
