THE HYDRODYNAMIC CHARACTERISTICS FOR VEGETATIVE CHANNEL WITH GRAVEL BED DUNES

Muhammad Azizol Mohd Yusof; Suraya  Sharil; Wan Hanna Melini  Wan Mohtar

doi:10.11113/jurnalteknologi.v84.17045

Authors

Muhammad Azizol Mohd Yusof Civil Engineering Department, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia https://orcid.org/0000-0003-0741-9691
Suraya Sharil Civil Engineering Department, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia
Wan Hanna Melini Wan Mohtar Civil Engineering Department, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia

DOI:

https://doi.org/10.11113/jurnalteknologi.v84.17045

Keywords:

Hydrodynamic, vegetative channel flow, dunes bed flow, turbulence intensity, turbulence kinetic energy time video

Abstract

Aquatic plants are known to provide flow resistance and impact the turbulence intensity and turbulent kinetic energy within the vegetated area. This paper further investigates the impact of both vegetation and dunes in open channels to the hydrodynamic characteristic of flow. Emergent vegetations were built from rigid wooden rod in staggered arrangement with 0.5% vegetations density were applied in the flume. Experiments were conducted with flow rate of 0.0058 m³/s throughout the experiments. Dunes were constructed from gravel of 2 mm size diameter in the shape of standing waves of three different lee slope angles of 3⁰, 6⁰ and 9⁰. Flow velocities are measured by using a velocimeter to get the raw data for the three-dimensional flow velocity in the x, y, and z directions. The velocities data were then analysed to calculate the mean velocity, turbulence intensity and turbulent kinetic energy. Experimental results showed that, for all three lee slope angles presented higher flow velocity in the vegetated channel compared to the non-vegetated channel. It was also found that greater lee slope angle dunes generate higher velocity for both channels with and without vegetation. Higher turbulence intensity can be found near the bed area and greater turbulence intensity also shown in the positive slope of a dunes compared to negative slope area. Higher turbulent kinetic energy values were recorded within the vegetated channel compared to the non-vegetated channels.

References

Afzalimehr, H., Maddahi, M. R., & Sui, J. 2017. Bedform Characteristics in a Gravel-bed River. Journal of Hydrology and Hydromechanics. 65(4): 366-377.

DOI: https://doi.org/10.1515/johh-2017-0023.

Afzalimehr, H., Maddahi, M. R., Sui, J., & Rahimpour, M. 2019. Impacts of Vegetation Over Bedforms on Flow Characteristics in Gravel-bed Rivers. Journal of Hydrodynamics. 31(5): 986-998.

DOI: https://doi.org/10.1007/s42241-019-0053-x.

Aliza Ahmad, N., Ali, Z. M., Mohd Arish, N. A., Mat Daud, A. M., & Amirah Alias, N. F. 2018. Determination of Flow Resistance Coefficient for Vegetation in Open Channel: Laboratory Study. IOP Conference Series: Earth and Environmental Science. 140(1): 0-7.

DOI: https://doi.org/10.1088/1755-1315/140/1/012019.

Chanson, H., Trevethan, M., & Aoki, S. 2008. Acoustic Doppler Velocimetry (ADV) in Small Estuary: Field Experience and Signal Post-Processing. 19: 307-313.

DOI: https://doi.org/10.1016/j.flowmeasinst.2008.03.003.

Dehsorkhi, E. N., Afzalimehr, H., Gallichand, J., & Rousseau, A. N. 2013. Turbulence Measurements above Sharp-crested Gravel Bedforms. International Journal of Hydraulic Engineering. 2(5): 101-114.

DOI: https://doi.org/10.5923/j.ijhe.20130205.04.

Dey, S., Paul, P., Fang, H., & Padhi, E. 2020. Hydrodynamics of Flow Over Two-dimensional Dunes. Physics of Fluids. 32(2).

DOI: https://doi.org/10.1063/1.5144552.

Ghoshal, K., & Pal, D. 2014. Grain-size Distribution in Suspension Over a Sand-gravel Bed in Open Channel Flow. International Journal of Sediment Research. 29(2): 184-194.

DOI: https://doi.org/10.1016/S1001-6279(14)60035-4.

Gualtieri, C. 2016. Hydrodynamics and Transverse Mixing in a Rectangular Channel with Bed Forms and Bank Vegetation Hydrodynamics and Transverse Mixing in a Rectangular Channel with Bed Forms and Bank. May.

Kabiri, F., Afzalimehr, H., & Sui, J. 2017. Flow Structure Over a Wavy Bed with Vegetation Cover. International Journal of Sediment Research. 32(2): 186-194.

DOI: https://doi.org/10.1016/j.ijsrc.2016.07.004.

Kwoll, E., Venditti, J. G., Bradley, R. W., & Winter, C. 2016. Journal of Geophysical Research: Earth Surface.

DOI: https://doi.org/10.1002/2015JF003637.

Liu, D., Diplas, P., Fairbanks, J. D., & Hodges, C. C. 2008. An Experimental Study of Flow through Rigid Vegetation. Journal of Geophysical Research: Earth Surface. 113(4): 1-16.

DOI: https://doi.org/10.1029/2008JF001042.

Maji, S, Pal, D., Hanmaiahgari, P. R., & Pu, J. H. 2016. Phenomenological Features of Turbulent Hydrodynamics in Sparsely Vegetated Open Channel Flow. 9(6): 2865-2875.

DOI:10.29252/jafm.09.06.26202.

Maji, Soumen, Hanmaiahgari, P. R., Balachandar, R., Pu, J. H., Ricardo, A. M., & Ferreira, R. M. L. 2020. A Review on Hydrodynamics of Free Surface Flows in Emergent Vegetated Channels. Water (Switzerland). 12(4): 1-17.

DOI https://doi.org/10.3390/W12041218.

Miyab, N. M., Afzalimehr, H., & Singh, V. P. 2015. Experimental Investigation of Influence of Vegetation on Flow Turbulence. 4(3): 54-69.

DOI: https://doi.org/10.5923/j.ijhe.20150403.02.

Mohtar, W. H. M. W., Bassa, S. A., & Porhemmat, M. 2017. Grain Size Analysis of Surface Fluvial Sediments in Rivers in Kelantan, Malaysia. Sains Malaysiana. 46(5): 685-693.

DOI: https://doi.org/10.17576/jsm-2017-4605-02.

Nepf, H M. 2004. Vegetated Flow Dynamics Introduction : Scales of Morphology and Flow in a Tidal Marsh.

DOI: https://doi.org/10.1029/CE059p0137.

Nepf, Heidi M. 2012. Hydrodynamics of Vegetated Channels Hydrodynamics of Vegetated Channels. 1686.

DOI: https://doi.org/10.1080/00221686.2012.696559.

Stoesser, T., Asce, M., Kim, S. J., Diplas, P., & Asce, M. 2010. Turbulent Flow through Idealized Emergent Vegetation. December. 1003-1017.

DOI: https://doi.org/10.1061/(ASCE)HY.1943-7900.0000153.

Union, A. G., & Published, A. 2019. Near # Bed , Wave # Velocity for Sediment Resuspension Impact of Vegetation ‐ Generated Turbulence on the Critical , Near ‐ Bed , Wave ‐ Velocity for Sediment Resuspension.

DOI: https://doi.org/10.1029/2018WR024335.

WU, W., & HE, Z. 2009. Effects of Vegetation on Flow Conveyance and Sediment Transport Capacity. International Journal of Sediment Research. 24(3): 247-259.

DOI: https://doi.org/10.1016/S1001-6279(10)60001-7.

Zame, K. K. 2010. ETD Program.

Zhang, H., Wang, Z., Dai, L., & Xu, W. 2015. Influence of Vegetation on Turbulence Characteristics and Reynolds Shear Stress in Partly Vegetated Channel. Journal of Fluids Engineering, Transactions of the ASME. 137(6): 1-8.

DOI: https://doi.org/10.1115/1.4029608.

Zong, L., & Nepf, H. 2010. Flow and Deposition in and around a Finite Patch of Vegetation. Geomorphology. 116(3-4): 363-372.

DOI: https://doi.org/10.1016/j.geomorph.2009.11.020.