Abstract
In the present study, we have compared the turbulent hydrodynamics in open turbulent flow with and without an emergent and sparse vegetation patch. The rigid patch, located at the middle cross-sectional region, was made by acrylic cylindrical rods with regular spacing between them along streamwise and transverse directions. The measurements of flow velocity components were taken by a Nortek Vectrino Plus acoustic Doppler velocimeter, and experimental data were collected along cross section for vegetation-free fully developed flow and along the cross section which is located at the middle of the streamwise length of the vegetation patch. Inside the vegetation patch, we have observed decreased value of time-averaged streamwise velocity in comparison with those of the vegetation-free fully developed flow. The time-averaged values of transverse and vertical velocities show increased magnitude with respect to the corresponding values in the vegetation-free fully developed flow. Inside the vegetation patch, with increasing transverse length from right-hand sidewall to left-hand sidewall, the magnitudes of normal stresses gradually increase and exceed the corresponding magnitudes of normal stresses in the vegetation-free fully developed flow. Along the cross section inside the patch, the magnitudes of governing Reynolds shear stress are smaller than the corresponding values of Reynolds shear stress without the vegetation. Along the cross section inside the patch, the vectors of secondary current follow are directed towards the left-hand sidewall together with zigzag pattern in vertical direction. In the interior of the vegetation, the strength of anticlockwise vortex in terms of the magnitude of moment of momentum is greater than that of the vegetation-free fully developed flow.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Bennett, S.J., Wu, W., Alonso, C.V., Wang, S.S.: Modeling fluvial response to in-stream woody vegetation: implications for stream corridor restoration. Earth Surf. Proc. Land. 33(6), 890–909 (2008)
Chanson, H., Trevethan, M., Aoki, S.I.: Acoustic doppler velocimetry (ADV) in small estuary: field experience and signal post-processing. Flow Meas. Instrum. 19(5), 307–313 (2008)
Cheng, N.S.: Calculation of drag coefficient for arrays of emergent circular cylinders with pseudofluid model. J. Hydraul. Eng. 139(6), 602–611 (2012)
Goring, D.G., Nikora, V.I.: Despiking acoustic doppler velocimeter data. J. Hydraul. Eng. 128(1), 117–126 (2002)
Marelius, F., Sinha, S.K.: Experimental investigation of flow past submerged vanes. J. Hydraul. Eng. 124(5), 542–545 (1998)
Mori, N., Suzuki, T., Kakuno, S.: Noise of acoustic doppler velocimeter data in bubbly flows. J. Eng. Mech. 133(1), 122–125 (2007)
Musleh, F.A., Cruise, J.F.: Functional relationships of resistance in wide flood plains with rigid unsubmerged vegetation. J. Hydraul. Eng. 132(2), 163–171 (2006)
Nepf, H.M.: Flow and transport in regions with aquatic vegetation. Annu. Rev. Fluid Mech. 44, 123–142 (2012)
Ortiz, A.C., Ashton, A., Nepf, H.: Mean and turbulent velocity fields near rigid and flexible plants and the implications for deposition. J. Geophys. Res.: Earth Surf. 118(4), 2585–2599 (2013)
Stoesser, T., Kim, S.J., Diplas, P.: Turbulent flow through idealized emergent vegetation. J. Hydraul. Eng. 136(12), 1003–1017 (2010)
Vargas-Luna, A., Crosato, A., Uijttewaal, W.S.J.: Effects of vegetation on flow and sediment transport: comparative analyses and validation of predicting models. Earth Surf. Proc. Land. 40(2), 157–176 (2015)
Wahl, T.L.: Discussion of despiking acoustic doppler velocimeter data by Derek G. Goring and Vladimir I. Nikora. J. Hydraul. Eng. 129(6), 484–487 (2003)
White, B.L., Nepf, H.M.: Shear instability and coherent structures in shallow flow adjacent to porous layer. J. Fluid Mech. 593, 1–32 (2007)
Zhang, H., Wang, Z., Dai, L., Xu, W.: Influence of vegetation on turbulence characteristics and reynolds shear stress in partly vegetated channel. J. Fluids Eng. 137(6), 061,201 (8 pages) (2015)
Zhao, K., Cheng, N.S., Wang, X., Tan, S.K.: Measurements of fluctuation in drag acting on rigid cylinder array in open channel flow. J. Hydraul. Eng. 140(1), 48–55 (2013)
Acknowledgements
IIT Kharagpur has given financial assistance to the first author Debasish Pal through a SRIC project (code: FVP).
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2017 Springer International Publishing AG
About this paper
Cite this paper
Pal, D., Halder, B., Hanmaiahgari, P.R. (2017). Comparison of Turbulent Hydrodynamics with and without Emergent and Sparse Vegetation Patch in Free Surface Flow. In: Garg, V., Singh, V., Raj, V. (eds) Development of Water Resources in India. Water Science and Technology Library, vol 75. Springer, Cham. https://doi.org/10.1007/978-3-319-55125-8_18
Download citation
DOI: https://doi.org/10.1007/978-3-319-55125-8_18
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-55124-1
Online ISBN: 978-3-319-55125-8
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)