Turbulent structure in unsteady depth-varying open-channel flows

被引:75
作者
Nezu, I
Kadota, A
Nakagawa, H
机构
[1] EHIME UNIV,DEPT CIVIL ENGN,MATSUYAMA,EHIME 770,JAPAN
[2] RITSUMEIKAN UNIV,DEPT CIVIL ENGN,KUSATSU 525,JAPAN
来源
JOURNAL OF HYDRAULIC ENGINEERING-ASCE | 1997年 / 123卷 / 09期
关键词
D O I
10.1061/(ASCE)0733-9429(1997)123:9(752)
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
Turbulence measurements over a smooth wall in unsteady depth-varying open-channel flows were conducted by the simultaneous use of a two-component laser Doppler anemometer (LDA) and a water-wave gauge. In the present study, velocity measurements in the viscous sublayer of highly unsteady flow have been first conducted to evaluate the friction velocity independently of the log-law. The von Karman constant kappa was calculated using this friction velocity. It was proven then that the value of kappa was really a constant of 0.41 even in unsteady open-channel flows. Next, statistical structures of mean velocity and turbulence characteristics were investigated across the whole flow from the near-wall region up to the free surface. In particular, turbulence measurements near the depth-varying water-surface zone of flood flow were conducted successfully for the first time with the LDA; such measurements have been impossible with conventional velocity instruments such as hot-film anemometers. Mean velocity profiles and turbulence characteristics were revealed in both the rising and the falling stages of the flood period.
引用
收藏
页码:752 / 763
页数:12
相关论文
共 18 条
[1]   AN INVESTIGATION OF TRANSITION TO TURBULENCE IN BOUNDED OSCILLATORY STOKES FLOWS .1. EXPERIMENTS [J].
AKHAVAN, R ;
KAMM, RD ;
SHAPIRO, AH .
JOURNAL OF FLUID MECHANICS, 1991, 225 :395-422
[2]  
Brereton GJ., 1995, APPL MECH REV, V48, P189, DOI DOI 10.1115/1.3005100
[3]  
French RH, 1985, OPEN CHANNEL HYDRAUL
[4]  
Hayashi T., 1988, P 20 S TURB, P154
[5]   TURBULENT OSCILLATORY BOUNDARY-LAYERS AT HIGH REYNOLDS-NUMBERS [J].
JENSEN, BL ;
SUMER, BM ;
FREDSOE, J .
JOURNAL OF FLUID MECHANICS, 1989, 206 :265-297
[6]  
Nagano Y., 1993, TURBULENT SHEAR FLOW, V8, P7, DOI DOI 10.1007/978-3-642-77674-82
[7]   OPEN-CHANNEL FLOW MEASUREMENTS WITH A LASER DOPPLER ANEMOMETER [J].
NEZU, I ;
RODI, W .
JOURNAL OF HYDRAULIC ENGINEERING, 1986, 112 (05) :335-355
[8]  
NEZU I, 1993, P 1993 HYDR C ASCE N, P1458
[9]  
NEZU I, 1995, P 10 S TURB SHEAR FL
[10]  
Nezu I., 1993, IAHR MONOGRAPH SERIE