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|Title:||Direct numerical simulation of turbulent transition for plane couette flows using full Navier-Stokes equations|
|Source:||Dou, H.-S.,Khoo, B.C. (2012). Direct numerical simulation of turbulent transition for plane couette flows using full Navier-Stokes equations. 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition : -. ScholarBank@NUS Repository. https://doi.org/10.2514/6.2012-891|
|Abstract:||Direct numerical simulation (DNS) of turbulent transition for plane Couette flows using full Navier-Stokes equations is performed. The governing equations are the unsteady three-dimensional (3D) Navier-Stokes equations. The numerical method is the fractional step method, in which the second order backward temporal scheme is used for temporal discretization, and the finite volume method with second order central difference scheme is used for space discretization. In the computing, geometric multigrid method and parallel computing with domain decomposition are employed. For plane Couette flow between two moving walls in opposite directions, the DNS results show that the critical Reynolds number (minimum Re) for turbulent transition is about 320∼375, which is in agreement with the simulations and experiments from others in literature. It is found that the disturbance leads to local distortion of the velocity profile, and forms a wave packet which results in the formation of the turbulent spot. The results from the DNS also support the proposed criterion of turbulent transition based on the energy gradient method in our previous works. That is, when the turbulent transition occurs at a Reynolds number larger than (or equaling) the minimum Rec, a zero velocity gradient is always present on the mean velocity profile under the disturbance influence. At Reynolds number lower than the minimum Rec, the disturbance decays and turbulent transition does not occur because zero velocity gradient is not produced regardless of the initial disturbance amplitude. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.|
|Source Title:||50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition|
|Appears in Collections:||Staff Publications|
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