| Mechanism of Breakdown in Laminar-Turbulent Transition of Incompressible Boundary Layer on a Flat Plate |
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| 作者姓名： | 唐洪涛 罗纪生 周恒 |
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| 作者单位： | School of Mechanical Engineering Tianjin University，School of Mechanical Engineering Tianjin University，School of Mechanical Engineering Tianjin University，Tianjin 300072 China School of Mechanical Engineering Tianjin University of Science and Technology Tianjin 300222 China，Tianjin 300072 China Liu Hui Center of Applied Mathematics Nankai University and Tianjin University Tianjin 300071 China，Tianjin 300072 China Liu Hui Center of Applied Mathematics Nankai University and Tianjin University Tianjin 300071 China |
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| 摘 要： | Temporal mode direct numerical simulation was done for the process of laminar-turbulent transition in an incompressible boundary layer on a flat plate. The analysis of the results showed that during the breakdown process of laminar-turbulent transition, the modification of the mean flow profile by the disturbances led to a remarkable change in its stability characteristics, manifested in the significant enlargement of the linear unstable zone and the maximum amplification rate, and led to that many more disturbances were excited and enhanced rapidly, correspondingly the turbulent energy also increased rapidly, and the mean flow profiles evolved swiftly from laminar to turbulent. It was also found that if the oblique waves in the initial disturbances did not form symmetrical pairs, the subsequent span-wise mean velocities would, in general, be nonzero due to nonlinear interaction, which would have a great effect on the stability characteristics and also implied that the turbulence obtained by direct numerical simulation might not be fully a random process.
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| 关 键 词： | 平板 不可压缩边界层 层流 湍流 转捩 崩溃机理 |
| 收稿时间： | 2007-01-25 |
Mechanism of Breakdown in Laminar-Turbulent Transition of Incompressible Boundary Layer on a Flat Plate |
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| TANG Hongtao,LUO Jisheng,ZHOU Heng.Mechanism of Breakdown in Laminar-Turbulent Transition of Incompressible Boundary Layer on a Flat Plate[J].Transactions of Tianjin University,2007,13(2):79-87. |
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| Authors: | TANG Hongtao LUO Jisheng ZHOU Heng |
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| Abstract: | Temporal mode direct numerical simulation was done for the process of laminar-turbulent transition in an incompressible boundary layer on a flat plate. The analysis of the results showed that during the breakdown process of laminar-turbulent transition, the modification of the mean flow profile by the disturbances led to a remarkable change in its stability characteristics, manifested in the significant enlargement of the linear unstable zone and the maximum amplification rate, and led to that many more disturbances were excited and enhanced rapidly, correspondingly the turbulent energy also increased rapidly, and the mean flow profiles evolved swiftly from laminar to turbulent. It was also found that if the oblique waves in the initial disturbances did not form symmetrical pairs, the subsequent span-wise mean velocities would, in general, be nonzero due to nonlinear interaction, which would have a great effect on the stability characteristics and also implied that the turbulence obtained by direct numerical simulation might not be fully a random process. |
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| Keywords: | boundary layer transition direct numerical simulation breakdown |
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