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Coherent structure of a d-type rough wall boundary layer by means of the vita analysis : low reynolds number effect

Memoirs of the Faculty of Engineering, Yamaguchi University Volume 44 Issue 2 Page 333-341
published_at 1994-03
KJ00000156971.pdf
[fulltext] 631 KB
Title
VITA法によるd形粗面境界層の組織構造の解析 : 低レイノルズ数の効果
Coherent structure of a d-type rough wall boundary layer by means of the vita analysis : low reynolds number effect
Creators Mochizuki Shinsuke
Creators Osaka Hideo
Source Identifiers
In order to examine the Reynolds number effect on the turbulent structure of a d-type rough wall boundary later, the bursting phenomenon which had major contribution to the turbulent production was investigated by means of the VITA analysis. The mean bursting frequency and conditional averaged velocity patterns of u, v and uv components were obtained in the low Reynolds number range of R_θ=800-5000. The scaling of the mean bursting frequency with the conventional scales in boundary layers, inner, outer and mixed time scales fails in the low Reynolds number range of the present d-type rough wall flow. The peak value and time duration of the conditional averaged signals both in the ejection and sweep processes depend on the Reynolds number in the transitional rough regime of R_θ<2000. It is expected that the behavior of the non-linear interaction between the boundary layer and low momentum fluid particle in the transverse grooves, which leads enhancement of the momentum exchange and large turbulent production rate is essential to describe the Reynolds number effect over the d-type roughness.
Languages jpn
Resource Type departmental bulletin paper
Publishers 山口大学工学部
Date Issued 1994-03
File Version Version of Record
Access Rights open access
Relations
[ISSN]0372-7661
[NCID]AN00244228
Schools 工学部