Turbulent Structures in Open-Channel
Flow with Emergent and Sparse
Vegetation
Soumen Maji, Nooka Raju Gompa, Prashanth Reddy Hanmaiahgari
and Vikas Garg
Abstract Important turbulent characteristics are compared between upstream,
interior and downstream of a sparse and emergent vegetation patch along the
centerline in an open-channel flow. The emergent vegetation patch is made up of
seventy uniform rigid acrylic cylindrical rods with regular spacing between two
cylinders along streamwise and lateral directions. Along the centerline from
upstream to downstream through the interior of the vegetation patch, time-averaged
streamwise and lateral velocities are decreasing whereas vertical velocities are
increasing. The profiles of streamwise lateral and vertical normal stresses, and
turbulent kinetic energy increase in downstream direction through the vegetation
patch along the centerline but slightly decrease in the wake region immediate
downstream of the trailing edge as compared the values in the middle region of the
vegetation patch. The dominant Reynolds shear stress u
0
w
0
profiles show
decreasing trend in the downstream direction inside the vegetation patch and in the
wake region downstream of trailing edge. The vertical distribution of u
0
v
0
shows
negative values at the leading edge of the vegetation patch, but positive at interior
and immediate downstream of the vegetation patch, which demonstrates increased
lateral momentum transfer in downstream direction along the vegetation patch.
Keywords Turbulent flow
Streamwise variation
Emergent vegetation
Sparse
vegetation
Open-channel
S. Maji (&) N.R. Gompa P.R. Hanmaiahgari
Department of Civil Engineering, IIT Kharagpur, Kharagpur 721302, India
e-mail: soumen@civil.iitkgp.ernet.in; soumen.maji184@gmail.com
N.R. Gompa
e-mail: rajugompa1@gmail.com
P.R. Hanmaiahgari
e-mail: hpr@civil.iitkgp.ernet.in
V. Garg
Department of Civil Engineering, UPES, Dehradun 248007, India
e-mail: gargvikas27@gmail.com
© Springer International Publishing AG 2017
V. Garg et al. (eds.), Development of Water Resources in India,
Water Science and Technology Library 75, DOI 10.1007/978-3-319-55125-8_36
419