مطالعه آزمایشگاهی اثر پوشش گیاهی سیلابدشت بر روی هیدرولیک جریان در کانال‌های مرکب واگرا

نوع مقاله : مقاله کامل (پژوهشی)

نویسندگان

1 گروه مهندسی آب دانشگاه لرستان

2 گروه مهندسی آب، دانشکده کشاورزی دانشگاه لرستان

چکیده

این تحقیق، به بررسی پارامترهای جریان و آشفتگی در یک کانال مرکب غیرمنشوری نامتقارن با تراکم‌های مختلف پوشش گیاهی صلب در سیلابدشت واگرا پرداخته است. آزمایش‌ها در شرایط پوشش گیاهی غیرمستغرق و با سه نسبت فاصله 5، 5/7 و 10 انجام شدند. نتایج بدست آمده نشان می‌دهد که سرعت جریان در سیلابدشت با پوشش گیاهی در مقایسه با حالت بدون پوشش به ترتیب در منطقه میانی و انتهای محدوده واگرایی بطور متوسط در حدود60 و 69 درصد کاهش می‌یابد. تنش برشی بستر نیز بدلیل مقاومت اضافی در برابر جریان ناشی از حضور پوشش گیاهی کاهش چشمگیری در ناحیه سیلابدشت نشان می‌دهد که برای منطقه میانی و انتهای واگرایی به ترتیب برابر با 5/78 و 86 درصد می‌باشد. همچنین تولید و استهلاک تنش‌های برشی رینولدزی و لایه برشی تشکیل شده به تناوب گردابه‌ای تشکیل شده در پشت هر میله منفرد بستگی دارد و بسیار ناپایدار می‌باشد. در انتها رابطه‌ای جهت برآورد مقدار ضریب اصطکاک بر اساس عدد رینولدز میله ارائه گردید و جهت محاسبه فرکانس گردابه‌های تشکیل شده در پشت المان‌های موجود بر روی سیلابدشت و ضریب دراگ موضعی نیز روابطی پیشنهاد شده است.

کلیدواژه‌ها


Ahmad, M., Ghani, U., Anjum, N., Pasha, G.A., Ullah, M.K. and Ahmed, A. (2020). Investigating the flow hydrodynamics in a compound channel with layered vegetated floodplains. Civil Engineering Journal, 6(5), 860-876.
Barrios-Piña, H., Ramírez-León, H., Rodríguez-Cuevas, C. and Couder-Castañeda, C. (2014). Multilayer numerical modeling of flows through vegetation using a mixing-length turbulence model. Water, 6(7), 2084-2103.
Bousmar, D. and Zech, Y. (1999). Momentum transfer for practical flow computation in compound channels. Journal of hydraulic engineering, 125(7), 696-706.
Bousmar, D. and Zech, Y. (2004). Velocity distribution in non-prismatic compound channels. In Proceedings of the Institution of Civil Engineers-Water Management, 157(2), 99-108, Thomas Telford Ltd.
Bousmar, D., Wilkin, N., Jacquemart, J.H. and Zech, Y. (2004). Overbank flow in symmetrically narrowing floodplains. Journal of hydraulic engineering, 130(4), 305-312.
Das, B.S. and Khatua, K.K. (2018). Flow resistance in a compound channel with diverging and converging floodplains. Journal of Hydraulic Engineering, 144(8), 04018051.
Das, B.S. and Khatua, K.K. (2019). Water surface profile computation for compound channel having diverging floodplains. ISH Journal of Hydraulic Engineering, 25(3), 336-349.
Das, B.S., Khatua, K.K. and Devi, K. (2017). Numerical solution of depth-averaged velocity and boundary shear stress distribution in converging compound channels. Arabian Journal for Science and Engineering, 42(3), 1305-1319.
Dean, R.G. and Dalrymple, R.A. (1984). Water wave mechanics for engineers and scientists. In Unknown Host Publication Title. Prentice-Hall Inc, 368 p.
Devi, K., Das, B.S., Khuntia, J.R. and Khatua, K.K. (2018). Analytical solution of non-uniform flow in compound channel. In E3S Web of Conferences, 40, p. 06041, EDP Sciences.
Dupuis, V., Proust, S., Berni, C., Paquier, A. and Thollet, F. (2015, June). Open-channel flow over longitudinal roughness transition from highly submerged to emergent vegetation. E-proceedings of the 36th IAHR World Congress,28 June – 3 July, 2015, The Hague, the Netherlands.
Ghisalberti, M. and Nepf, H.M. (2004). The limited growth of vegetated shear layers. Water Resources Research, 40(7), W07502, doi:10.1029/2003WR 002776
Hamidifar, H., Omid, M.H. and Keshavarzi, A. (2016). Kinetic energy and momentum correction coefficients in straight compound channels with vegetated floodplain. Journal of Hydrology, 537, 10-17.
Hu, C., Ji, Z. and Guo, Q. (2010). Flow movement and sediment transport in compound channels. Journal of Hydraulic Research, 48(1), 23-32.
Jafari, A., Ghomeshi, M., Bina, M. and Kashefipour, S.M. (2011). A new equation for simulating strouhal number of wave frequency due to flow passing through cylinder obstacles. Irrigation Sciences and Engineering (JISE), 34(1), 45-54, (in Persian).
James, C.S., Birkhead, A.L., Jordanova, A.A. and O'sullivan, J.J. (2004). Flow resistance of emergent vegetation. Journal of Hydraulic Research, 42(4), 390-398.
Jing, H., Li, C., Guo, Y. and Xu, W. (2011). Numerical simulation of turbulent flows in trapezoidal meandering compound open channels. International journal for numerical methods in fluids, 65(9), 1071-1083.
Keulegan, G.H. (1938). Laws of turbulent flow in open channels. US: National Bureau of Standards, (21), 707-741.
Knight, D.W. and Demetriou, J.D. (1983). Flood plain and main channel flow interaction. Journal of Hydraulic Engineering, 109(8), 1073-1092.
Knight, D.W. and Hamed, M.E. (1984). Boundary shear in symmetrical compound channels. Journal of Hydraulic Engineering, 110(10), 1412-1430.
Knight, D.W. and Shiono, K. (1990). Turbulence measurements in a shear layer region of a compound channel. Journal of hydraulic research, 28(2), 175-196.
Koftis, T. and Prinos, P. (2018). Reynolds stress modelling of flow in compound channels with vegetated floodplains. Journal of Applied Water Engineering and Research, 6(1), 17-27.
Kothyari, U.C., Hayashi, K. and Hashimoto, H. (2009). Drag coefficient of unsubmerged rigid vegetation stems in open channel flows. Journal of Hydraulic Research, 47(6), 691-699.
Lu, S. and Chen, J. (2014). Effects of Rigid Vegetation on the Turbulence Characteristics in Sediment-Laden Flows. Journal of Applied Mathematics and Physics, 2(12), 1091-1098.
Mulahasan, S., Stoesser, T. and McSherry, R. (2017). Effect of floodplain obstructions on the discharge conveyance capacity of compound channels. Journal of Irrigation and Drainage Engineering, 143(11), 04017045.
Musleh, F.A. and Cruise, J.F. (2006). Functional relationships of resistance in wide flood plains with rigid unsubmerged vegetation. Journal of hydraulic engineering, 132(2), 163-171.
Naik, B., Khatua, K.K., Padhi, E. and Singh, P. (2018). Loss of energy in the converging compound open channels. Arabian Journal for Science and Engineering, 43(10), 5119-5127.
Pasche, E. (1984). Turbulence mechanism in natural streams and the possibility of  its mechanical representation. Mitteilungen Institut für Wasserbau and Wasserwirtschaft, (52).
Pasche, E. and Rouvé, G. (1985). Overbank flow with vegetatively roughened flood plains. Journal of Hydraulic Engineering, 111(9), 1262-1278.
Proust, S., Riviere, N., Bousmar, D., Paquier, A., Zech, Y. and Morel, R. (2006). Flow in compound channel with abrupt floodplain contraction. Journal of hydraulic engineering, 132(9), 958-970.
Rameshwaran, P. and Shiono, K. (2007). Quasi two-dimensional model for straight overbank flows through emergent. Journal of Hydraulic Research, 45(3), 302-315.
Rezaei, B. and Knight, D.W. (2009). Application of the Shiono and Knight Method in compound channels with non-prismatic floodplains. Journal of Hydraulic Research, 47(6), 716-726.
Rezaei, B. and Knight, D.W. (2011). Overbank flow in compound channels with nonprismatic floodplains. Journal of Hydraulic Engineering, 137(8), 815-824.
Roshko, A. (1954). A new hodograph for free-streamline theory, https://digital.library.unt.edu /ark:/67531/metadc57027/.
Sanjou, M. and Nezu, I. (2011). Turbulence structure and concentration exchange property in compound open-channel flows with emergent trees on the floodplain edge. International journal of river basin management, 9(3-4), 181-193.
Sanjou, M., Nezu, I., Suzuki, S. and Itai, K. (2010). Turbulence structure of compound open-channel flows with one-line emergent vegetation. Journal of Hydrodynamics, 22(1), 560-564.
Sarkar, A. (2012). Vortex-excited transverse surface waves in an array of randomly placed circular cylinders. Journal of Hydraulic Engineering, 138(7), 610-618.
Schlichting, H. (1968). Boundary layer theory. McGraw-Hill, New York, 817 p.
Sellin, R.H.J. (1964). A laboratory investigation into the interaction between the flow in the channel of a river and that over its flood plain. La Houille Blanche, (7), 793-802.
Shiono, K. and Knight, D.W. (1991). Turbulent open-channel flows with variable depth across the channel. Journal of Fluid Mechanics, 222, 617-646.
Sonnenwald, F., Stovin, V. and Guymer, I. (2019). Estimating drag coefficient for arrays of rigid cylinders representing emergent vegetation. Journal of Hydraulic Research, 57(4), 591-597.
Stoesser, T., Kim, S.J. and Diplas, P. (2010). Turbulent flow through idealized emergent vegetation. Journal of Hydraulic Engineering, 136(12), 1003–1017.
Stoesser, T., Kim, S.J. and Diplas, P. (2010). Turbulent flow through idealized emergent vegetation. Journal of Hydraulic Engineering, 136(12), 1003-1017.
Sun, X. and Shiono, K. (2009). Flow resistance of one-line emergent vegetation along the floodplain edge of a compound open channel. Advances in Water Resources, 32(3), 430-438.
Sun, X., Shiono, K., Fu, X.Y., Yang, K.J. and Huang, T.L. (2013). Application of Shiono and Knight method to compound open channel flow with one-line emergent vegetation. In Advanced Materials Research. Trans Tech Publications Ltd. 663, 930-935.
Takemura, T. and Tanaka, N. (2007). Flow structures and drag characteristics of a colony-type emergent roughness model mounted on a flat plate in uniform flow. Fluid dynamics research, 39(9-10), 694.
Tang, X. and Knight, D.W. (2009). Lateral distributions of streamwise velocity in compound channels with partially vegetated floodplains. Science in China Series E: Technological Sciences, 52(11), 3357-3362.
Tang, X., Knight, D.W. and Sterling, M. (2011). Analytical model for streamwise velocity in vegetated channels. Proceedings of the Institution of Civil Engineers-Engineering and Computational Mechanics, 164(2), 91-102.
Terrier, B. (2010). Flow characteristics in straight compound channels with vegetation along the main channel. Ph.D Thesis, Loughborough University, 353p.
Terrier, B., Robinson, S., Shiono, K., Paquier, A. and Ishigaki, T. (2010). Influence of vegetation to boundary shear stress in open channel for overbank flow. River Flow 2010, 285-292.
Västilä, K., Järvelä, J. and Koivusalo, H. (2016). Flow–vegetation–sediment interaction in a cohesive compound channel. Journal of Hydraulic Engineering, 142(1), 04015034.
Wang, W.J., Peng, W.Q., Huai, W.X., Katul, G.G., Liu, X.B., Qu, X.D. and Dong, F. (2019). Friction factor for turbulent open channel flow covered by vegetation. Scientific reports, 9(1), 1-16.
Yang, J.Q. and Nepf, H.M. (2019). Impact of vegetation on bed load transport rate and bedform characteristics. Water Resources Research, 55(7), 6109-6124.
Yang, K., Cao, S. and Knight, D.W. (2007). Flow patterns in compound channels with vegetated floodplains. Journal of Hydraulic Engineering, 133(2), 148-159.
Yang, K., Nie, R., Liu, X. and Cao, S. (2013). Modeling depth-averaged velocity and boundary shear stress in rectangular compound channels with secondary flows. Journal of Hydraulic Engineering, 139(1), 76-83.
Yonesi, H.A., Omid, M.H. and Ayyoubzadeh, S.A. (2013). The hydraulics of flow in non-prismatic compound channels. J Civil Eng Urban, 3(6), 342-356.
Zdravkovich, M.M. (1987). The effects of interference between circular cylinders in cross flow. Journal of fluids and structures, 1(2), 239-261.
Zhang, M., Jiang, C., Huang, H., Nanson, G.C., Chen, Z. and Yao, W. (2017). Analytical models for velocity distributions in compound channels with emerged and submerged vegetated floodplains. Chinese Geographical Science, 27(4), 577-588.
Zhao, K., Cheng, N.S. and Huang, Z. (2014). Experimental study of free-surface fluctuations in open-channel flow in the presence of periodic cylinder arrays. Journal of Hydraulic Research, 52(4), 465-475.
Zong, L. and Nepf, H. (2010). Flow and deposition in and around a finite patch of vegetation. Geomorphology, 116(3-4), 363-372.