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旋轉圓盤內流場的動態次格點模型大渦數值模擬
Thesis

旋轉圓盤內流場的動態次格點模型大渦數值模擬

陳昭文
Masters, National Tsing Hua University
2002

Abstract

旋轉圓盤次格點大渦數值模擬旋渦紊流強度 rotor-stator cavitysubgridlarge eddy simulationvorticityturbulence intensity
The main focus of the present work is to explore the effects of the dynamic model in large eddy simulations. Application is first applied to the fully developed channel flow with Reynolds number at . It was found that the dynamic model is more sensitive to the grid density compared to that using the van Driest damping. Both the sub-grid models with van Direst damping and the dynamic model predict the mean and turbulence quantities well by comparisons with the DNS data. The viscous sub-layer is adequately resolved by the models. However, the dynamic model does predict a lower level of turbulence intensity at the central core of the channel. For rotor-stator flow, the internal structure is induced by the diffusive transport of the tangential momentum from the rotor into interior. A secondary flow exits within the rotor-stator cavity. The instantaneous azimuthal vorticity contours show stretching and elongated structure in the tangential direction. Near the rotor, the vorticity structure is more coherent; but near the stator the vorticity structure is more chaotic. Comparisons with the available measured data, both models show good results, though there are some discrepancies across the Ekmann layers.

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