Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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A Direct Numerical Simulation Study on the very Large-Scale Motion in Turbulent Boundary Layer

직접수치모사를 이용한 난류경계층 내의 거대난류구조 연구

  • 이재화 (한국과학기술원 기계공학과) ;
  • 성형진 (한국과학기술원 기계공학과)
  • Published : 2009.12.01
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Abstract

Direct numerical simulation (DNS) of a turbulent boundary layer with moderate Reynolds number was performed to scrutinize streamwise-coherence of hairpin packet motions. The Reynolds number based on the momentum thickness (${\theta}_{in}$) and free-stream velocity (U${\infty}$) was varied in the range $Re_{\theta}$=1410${\sim}$2540 which was higher than the previous numerical simulations in the turbulent boundary layer. In order to include the groups of hairpin packets existing in the outer layer, large computational domain was used (more than 50${\delta}_o$, where ${\theta}_o$ is the boundary layer thickness at the inlet in the streamwise domain). Characteristics of packet motions were investigated by using instantaneous flow fields, two-point correlation and conditional average flow fields in xy-plane. The present results showed that a train of hairpin packet motions was propagating coherently along the downstream and these structures induced the very large-scale motions in the turbulent boundary layer.

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References

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