- 관 내 과도 난류유동에 대한 대형와 모사
- ㆍ 저자명
- 정서윤,정용만,Jung. Seo-Yoon,Chung. Yong-Mann M.
- ㆍ 간행물명
- 大韓機械學會論文集. Transactions of the Korean society of mechanical engineers. B. B
- ㆍ 권/호정보
- 2008년|32권 9호|pp.720-727 (8 pages)
- ㆍ 발행정보
- 대한기계학회
- ㆍ 파일정보
- 정기간행물| PDF텍스트
- ㆍ 주제분야
- 기타
Time delay effects on near-wall turbulent structures are investigated by performing a large-eddy simulation of a transient turbulent flow in a pipe. To elucidate the time delay effects on the near-wall turbulence, we selected the dimensionless acceleration parameter which was used in the previous study. Various turbulent statistics revealed the distinctive features of the delay. It was shown that the dynamic Smagorinsky model is valid to capture the alterations of the turbulence physics well. A dimensionless time for the responses of the flow quantities was introduced to give the detailed information on the delay of the nearwall turbulence. The conditionally-averaged flow fields associated with Reynolds shear stress producing events show that sweep and ejections are closely related to the delays of the turbulence production and the turbulence propagation toward the pipe center. The present study suggested that the enhanced anisotropy of the turbulence in the initial and transient stages would be a challenging problem to standard turbulence models.