Analysis of the Coherent Structure of a d-Type Rough Wall Boundary Layer with the VITA Technique
Memoirs of the Faculty of Engineering, Yamaguchi University Volume 39 Issue 2
Page 337-343
published_at 1989-03
Title
VITA 法による d 形粗面境界層の組織構造 : 低レイノルズ数の場合
Analysis of the Coherent Structure of a d-Type Rough Wall Boundary Layer with the VITA Technique
Creators
Osaka Hideo
Source Identifiers
Conditional averages of the longitudinal, normal velocities and their products have been obtained using the VITA technique in a turbulet boundary layer over a d-type rough surface at a momentum thickness Reynolds number of R_θ≒800. It is shown that the ensemble averaged patterns reflect both the well known ejection and sweep events, even in the present low Reynolds number flow. Both ejections and sweeps made a strong, intermittent contribution to the Reynolds stress and the turbulence production. Near the wall, the ejection phase plays a predominant role. The normalized averaged bursting frequency is considerably larger for the present rough wall flow than the smooth wall flow at almost the same Reynolds number. It is inferred from the increase of both the width of the intermittent region and the entrainment rate that the width of the highly irregular interface between turbulent and non-turbulent flow fields increses with a decreasing Reynolds number.
Languages
jpn
Resource Type
departmental bulletin paper
Publishers
山口大学工学部
Date Issued
1989-03
File Version
Version of Record
Access Rights
open access
Relations
[ISSN]0372-7661
[NCID]AN00244228
Schools
工学部