TURBULENT DRAG REDUCTION IN A D-TYPE ROUGH WALL BOUNDARY-LAYER WITH LONGITUDINAL THIN RIBS PLACED WITHIN TRAVERSE GROOVES (HIGHER-ORDER MOMENTS AND CONDITIONAL SAMPLING ANALYSIS)

Authors
MOCHIZUKI S IZAWA A OSAKA H
Citation
S. Mochizuki et al., TURBULENT DRAG REDUCTION IN A D-TYPE ROUGH WALL BOUNDARY-LAYER WITH LONGITUDINAL THIN RIBS PLACED WITHIN TRAVERSE GROOVES (HIGHER-ORDER MOMENTS AND CONDITIONAL SAMPLING ANALYSIS), JSME international journal. Series B, fluids and thermal engineering, 39(3), 1996, pp. 461-469
Citations number
30
Categorie Soggetti
Engineering, Mechanical",Thermodynamics
Journal title
JSME international journal. Series B, fluids and thermal engineering → ACNP
ISSN journal
13408054
Volume
39
Issue
3
Year of publication
1996
Pages
461 - 469
Database
ISI
SICI code
1340-8054(1996)39:3<461:TDRIAD>2.0.ZU;2-7
Abstract
Large-scale coherent motions were investigated experimentally in a d-t ype rough wall boundary layer modified with longitudinal thin ribs. Hi gher-order moments and conditional averaged statistics were obtained a t R(theta)=1 300 and 5000, where the local skin friction coefficients of modified flow are the same as and about 17% larger than those of sm ooth wall flow. The magnitude of triple velocity correlations is reduc ed in most-of the layer by drag reduction control using longitudinal t hin ribs. The higher-order moments and conditional averaged signals ob tained by the VITA analysis show that the turbulence production model with a pair of streamwise vortices interacting with outflow from the r oughness grooves is reasonable.