Abstract
Influence of boulder concentration on the physical process of energy balance among the turbulent kinetic energy (TKE) budget terms in a gravel bed stream is investigated. Flow measurements were carried out in a rectangular open channel by an acoustic Doppler velocimeter (ADV) along the centre-line transects. An array of immobile boulders with large stream-wise boulder-to-boulder spacing was staggered over the gravel bed surface. Double averaging methodology (DAM) was used to analyse the measured data. The experimental results show that the TKE-budget components measured at the wake flow region differs significantly and the effect of large boulders extends up to five time of the boulder diameter in the wake flow region. The TKE production, diffusion and pressure energy diffusion rate components attains their peak values near the boulder crest level, while the TKE dissipation rate attains its peak value at the stream bed level. The results of turbulent kinetic energy budget distributions reveal to our understanding that the magnitude of the pressure energy diffusion rate at the near-bed region corroborates enhanced turbulence production which is attributed to vortex shedding and flow recirculation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
Aberle, J., Koll, K., and Dittrich, A., Form induced stresses over rough gravel-beds, Acta Geophys., 2008, vol. 56, no. 3, pp. 584–600.
Buffin-Bélanger, T. and Roy, A.G., Effects of a pebble cluster on the turbulent structure of a depth-limited flow in a gravel-bed river, Geomorpho., 1998, vol. 25, nos. 3–4, pp. 249–267.
Cao, H., Ye, C., Yan, X.-F., Liu, X.-N., and Wang, X.-K., Experimental investigation of turbulent flows through a boulder array placed on a permeable bed, Water Supply, 2020, vol. 20, no. 4, pp. 1281–1293.
Dey, S., Sarkar, S., Bose, S.K., Tait, S., and Castro-Orgaz, O., Wall-wake flows downstream of a sphere placed on a plane rough wall, J. Hydraul. Eng., 2011, vol. 137, no. 10, pp. 1173–1189.
Dey, S. and Das, R., Gravel-bed hydrodynamics: Double-averaging approach, J. Hydraul. Eng., 2012, vol. 138, no. 8, pp. 707–725.
Goring, D.G. and Nikora, V.I., Despiking acoustic Doppler velocimeter data, J. Hydraul. Eng., 2002, vol. 128, no. 1, pp. 117–126.
Lacey, R.W.J. and Roy, A.G., A comparative study of the turbulent flow field with and without a pebble cluster in a gravel bed river, Water Resour. Res., 2007, vol. 43, no. 5, W05502.
Manes, C., Pokrajac, D., McEwan, I.K., and Nikora, V., Turbulence structure of open channel flows over permeable and impermeable beds: A comparative study, Phy. Fluids, 2009, vol. 21, no. 12, 125109.
Mignot, E., Barthelemy, E., and Hurther, D., Double-averaging analysis and local flow characterization of near-bed turbulence in gravel-bed channel flow, J. Fluid. Mech., 2009, vol. 618, pp. 279–303.
Monin, A.S. and Yanglom, A.M., Statistical Fluid Mechanics, vol. II: Mechanics of Turbulence, New York: Dover Publications, 2007.
Nezu, I. and Nakagawa, H., Turbulence in Open-Channel Flows, Rotterdam: Balkema, Netherlands, 1993.
Nikora, V., Goring, D., McEwan, I., and Griffiths, G., Spatially averaged open-channel flow over rough bed, J. Hydraul. Eng., 2001, vol. 127, no. 2, pp. 123–133.
Nikora, V., McEwan, I., McLean, S., Coleman, S., Pokrajac, D., and Walters, R., Double-averaging concept for rough-bed open-channel and overland flows: theoretical background, J. Hydraul. Eng., 2007, vol. 133, no. 8, pp. 873–883.
Papanicolaou, A.N., Kramer, C.M., Tsakiris, A.G., Stoesser, T., Bomminayuni, S., and Chen, Z., Effects of a fully submerged boulder within a boulder array on the mean and turbulent flow fields: implications to bedload transport, ActaGeophys., 2012, vol. 60, no. 6, pp. 1502–1546.
Pope, S.B., Turbulent Flows, Cambridge University Press, 2001.
Sarkar, S. and Dey, S., Double-averaging turbulence characteristics in flows over a gravel bed, J. Hydraul. Res., 2010, vol. 48, no. 6, pp. 801–809.
Sarkar, S. and Dey, S., Turbulent length scales and anisotropy downstream of a wall mounted sphere, J. Hydraul. Res., 2015, vol. 53, no. 5, pp. 649–658.
Sarkar, S., Papanicolaou, A. N., and Dey, S., Turbulence in a gravel-bed stream with an array of large gravel obstacles, J. Hydraul. Eng., 2016, vol. 142, no. 11, 04016052.
Strom, K.B. and Papanicolaou, A.N., ADV measurements around a cluster microform in a shallow mountain stream, J. Hydraul. Eng., 2007, vol. 133, no. 12, pp. 1379–89.
Tsakiris, A.G., Papanicolaou, A.N., Hajimirzaie, S.M., and Buchholz, J.H.J., Influence of collective boulder array on the surrounding time-averaged and turbulent flow fields, J. Mt. Sci., 2014, vol. 11, no. 6, pp. 1420–1428.
Yager, E.M., Kirchner, J.W., and Dietrich, W.E., Calculating bed load transport in steep boulder bed channels, Water Resour. Res., 2007, vol. 43, no. 7, W07418.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
The authors declare that they have no conflicts of interest.
Additional information
Publisher’s Note.
Pleiades Publishing remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Datta, A., Das, R. Assessment of Turbulent Kinetic Energy Balance within the Boulder Array in Gravel Bed Stream. Water Resour 50, 868–876 (2023). https://doi.org/10.1134/S0097807823600110
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0097807823600110