From the perspective of vegetation density, this research studies the influence of vegetation on turbulence characteristics and Reynolds shear stress in partly vegetated channel via a series of experiments. Natural reed is employed to simulate the emergent vegetation in rivers. Different vegetation densities including vegetated and unvegetated cases are considered in the research. The results of the research demonstrate that emergent vegetation may force the water flowing from vegetated areas to unvegetated areas and the forcing intensity increases with reed density. It is also found that the relative turbulence intensity declines along the vegetated channel in the direction of flow. Vegetation is found to reduce the total-average Reynolds shear stress therefore reduce the soil erosion. However, the Reynolds shear stress reduction is found disproportional to the vegetation density, and an optimal vegetation density range is quantitatively determined in the research. The findings of the research are significant to the practice of river ecological restoration.

References

References
1.
Fathi-Maghadam
,
M.
, and
Kouwen
,
N.
,
1997
, “
Nonrigid, Nonsubmerged, Vegetative Roughness on Floodplains
,”
J. Hydraul. Eng.
,
123
(
1
), pp.
51
57
.10.1061/(ASCE)0733-9429(1997)123:1(51)
2.
López
,
F.
, and
García
,
M. H.
,
2001
, “
Mean Flow and Turbulence Structure of Open-Channel Flow Through Non-Emergent Vegetation
,”
J. Hydraul. Eng.
,
127
(
5
), pp.
392
402
.10.1061/(ASCE)0733-9429(2001)127:5(392)
3.
Schultz
,
M. P.
,
2000
, “
Turbulent Boundary Layers on Surfaces Covered With Filamentous Algae
,”
ASME J. Fluids Eng.
,
122
(
2
), pp.
357
363
.10.1115/1.483265
4.
Nikora
,
N.
,
Nikora
,
V.
, and
O'Donoghue
,
T.
,
2013
, “
Velocity Profiles in Vegetated Open-Channel Flows: Combined Effects of Multiple Mechanisms
,”
J. Hydraul. Eng.
,
139
(
10
), pp.
1021
1032
.10.1061/(ASCE)HY.1943-7900.0000779
5.
Jack
,
E. A.
,
Wafaa
,
S. K.
, and
Ghanem
,
F. O.
,
2011
, “
Particle Image Velocimetry Measurements in the Wake of a Cactus-Shaped Cylinder
,”
ASME J. Fluids Eng.
,
133
(
9
), p.
094502
.10.1115/1.4004824
6.
Musleh
,
F. A.
, and
Cruise
,
J. F.
,
2006
, “
Functional Relationships of Resistance in Wide Flood Plains With Rigid Unsubmerged Vegetation
,”
J. Hydraul. Eng.
,
132
(
2
), pp.
163
171
.10.1061/(ASCE)0733-9429(2006)132:2(163)
7.
Martino
,
R.
,
Paterson
,
A.
, and
Piva
,
M.
,
2014
, “
Water Level Rise Upstream a Permeable Barrier in Subcritical Flow: Experiment and Modeling
,”
ASME J. Fluids Eng.
,
136
(
4
), p.
041103
.10.1115/1.4026356
8.
Green
,
J. C.
,
2005
, “
Velocity and Turbulence Distribution Around Lotic Macrophytes
,”
Aquat. Ecol.
,
39
(
1
), pp.
1
10
.10.1007/s10452-004-1913-0
9.
Nepf
,
H. M.
,
1999
, “
Drag, Turbulence, and Diffusion in Flow Through Emergent Vegetation
,”
Water Resour. Res.
,
35
(
2
), pp.
479
489
.10.1029/1998WR900069
10.
McBride
,
M.
,
Hession
,
W. C.
,
Rizzo
,
D. M.
, and
Thompson
,
D. M.
,
2007
, “
The Influence of Riparian Vegetation on Near-Bank Turbulence: A Flume Experiment
,”
Earth Surf. Proc. Land.
,
32
(
13
), pp.
2019
2037
.10.1002/esp.1513
11.
Velasco
,
D.
,
Bateman
,
A.
,
Redondo
,
J. M.
, and
Demedina
,
V.
,
2003
, “
An Open Channel Flow Experimental and Theoretical Study of Resistance and Turbulent Characterization Over Flexible Vegetated Linings
,”
Flow Turbul. Combust.
,
70
(
1–4
), pp.
69
88
.10.1023/B:APPL.0000004932.81261.40
12.
Afzalimehr
,
H.
, and
Dey
,
S.
,
2009
, “
Influence of Bank Vegetation and Gravel Bed on Velocity and Reynolds Stress Distributions
,”
Int. J. Sediment Res.
,
24
(
2
), pp.
236
246
.10.1016/S1001-6279(09)60030-5
13.
Neary
, V
. S.
,
Constantinescu
,
S. G.
,
Bennett
,
S. J.
, and
Diplas
,
P.
,
2012
, “
Effects of Vegetation on Turbulence, Sediment Transport, and Stream Morphology
,”
J. Hydraul. Eng.
,
138
(
9
), pp.
765
776
.10.1061/(ASCE)HY.1943-7900.0000168
14.
Zhang
,
H. Y.
, and
Dai
,
L. M.
,
2009
, “
Surface Runoff and Its Erosion Energy in a Partially Continuous System: An Ecological Hydraulic Model
,”
ASME
Paper No. IMECE2009-10607.10.1115/IMECE2009-10607
15.
Aupoix
,
B.
,
2015
, “
Roughness Corrections for the k–ω Shear Stress Transport Model: Status and Proposals
,”
ASME J. Fluids Eng.
,
137
(
2
), p.
021202
.10.1115/1.4028122
16.
Chow
,
V. T.
,
1959
,
Open-Channel Hydraulics
,
McGraw-Hill
,
New York
, Chap. 9.
17.
Liu
,
C.
, and
Shen
,
Y. M.
,
2008
, “
Flow Structure and Sediment Transport With Impacts of Aquatic Vegetation
,”
J. Hydrodyn., Ser. B
,
20
(
4
), pp.
461
468
.10.1016/S1001-6058(08)60081-5
18.
Nepf
,
H. M.
, and
Vivoni
,
E. R.
,
2000
, “
Flow Structure in Depth-Limited, Vegetated Flow
,”
J. Geophys. Res.
,
105
(
C12
), pp.
28547
28557
.10.1029/2000JC900145
19.
Allmendinger
,
N. E.
,
Pizzuto
,
J. E.
,
Potter
,
N.
,
Johnson
,
T. E.
, and
Hession
,
W. C.
,
2005
, “
The Influence of Riparian Vegetation on Stream Width, Eastern Pennsylvania, USA
,”
Geol. Soc. Am. Bull.
,
117
(
1–2
), pp.
229
243
.10.1130/B25447.1
20.
Rowiński
,
P. M.
, and
Kubrak
,
J.
,
2002
, “
A Mixing-Length Model for Predicting Vertical Velocity Distribution in Flows Through Emergent Vegetation
,”
Hydrolog. Sci. J.
,
47
(
6
), pp.
893
904
.10.1080/02626660209492998
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