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Self-preservation of a turbulent boundary layer over d-type roughness

Journal of Fluid Science and Technology Volume 1 Issue 1 Page 24-35
published_at 2006
2007020193.pdf
[fulltext] 602 KB
Title
Self-preservation of a turbulent boundary layer over d-type roughness
Creators Mochizuki Shinsuke
Creators Kameda Takatsugu
Creators Osaka Hideo
Creator Keywords
turbulent flow boundary layer law of the wall d-type roughness
Using a direct drag balance measurement for the local wall shear stress, self-preserving development of a turbulent boundary layer was achieved experimentally over a d-type rough surface without pressure gradients. The wall shear stress and mean velocity measurements confirmed the requirements for exact self-similarity and highly similar Reynolds stress profiles within the Reynolds number range for a constant skin friction coefficient. Under the condition that the boundary layer flow is completely independent of Reynolds number, the effect of wall roughness was investigated with respect to the similarity laws for the wall layer as well as the outer layer. Experimental observation reveals the wall similarity ∂U/∂y = u_τ/ky to be applicable to the present rough wall boundary layer remaining the accepted value of Karman constant to be κ= 0.41. Otherwise, investigation of the wake strength in the mean velocity and Reynolds stress profiles reveals that the wall roughness does affect the outer layer structure. Reynolds stress measurements indicate that the primary effect of wall roughness on turbulence properties is in the component normal to the wall.
Languages eng
Resource Type journal article
Publishers The Japan Society of Mechanical Engineers
Date Issued 2006
File Version Version of Record
Access Rights open access
Relations
[ISSN]1880-5558
https://doi.org/10.1299/jfst.1.24
[isVersionOf] [URI]http://www.jstage.jst.go.jp/browse/jfst
Schools 大学院理工学研究科(工学)