J057014 平行平板間流における遷移レイノルズ数(〔J057-01〕乱流における運動量、熱、物質の輸送現象(1))

Abstract

Recently it is well known that localized turbulent structures in wall turbulence are transient and their survival probabilities decrease exponentially with respect to time. We measure lifetimes of streamweise-localize turbulence in channel flow by using direct numerical simulations. The dependence of a lifetime on span widths is roughly exponential. This indicates that a survival probability may be consider as combination of nearly independent Poisson processes that take place on each lowspeed streak.