大渦數值模擬結合沉浸邊界法及壁面函數分析複雜幾何形狀紊流流場

Large eddy simulations of complex geometry flows with wall function and Immersed Boundary Method

張伯華(Po-Hua Chang)

指導教授 ： 林昭安

國立清華大學/工學院/動力機械工程學系/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00169

摘要

Immersed boundary method and wall models are adopted to simulate the laminar and turbulent flows over periodic hills with large eddy simulation. The Reynolds numbers based on the hill hight are 25∼100 for the laminar flow, whereas are
2800, 5600 and 10595 for the turbulent flows. The results show that the flow over periodic hills consists of separation, recirculation and reattachment for the laminar and turbulent flows. The locations of separation and reattachment points are linear with the Reynolds number for laminar flows, but exhibit slightly difference with the Reynolds number for turbulent flows. For the simulation of turbulent flow over periodic hills, the results reveal that the present numerical treatment with grid resolutions (200 × 95 × 96) are sufficient for capturing the turbulence quantities compared with the DNS data of Breuer et al. [1] at lower Reynolds number Re = 2800. However, due to the inappropriate implement of wall model, the near wall turbulence is fail to be predicted as Reynolds number increased. It indicates that the adopted wall model with velocity correction could not accurately capture the near wall Reynolds stresses on the curvature wall boundary.

關鍵字

紊流 ； 沉浸邊界法 ； 大渦數值模擬

參考文獻

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[3] C.S. Peskin, The immersed boundary method. Acta. Numer. (2002) 459-517.

[4] R. Mittal, G. Iaccarino, Immersed boundary methods, Annu. Rev. Fluid Mech. 37 (2005) 239-261.

[5] D. Goldstein, R. Handler, L. Sirovich, Modeling a no-slip flow with an external force field, J. Comput. Phys. 105 (1993) 354-366.