Experimental Investigation of Supercritical Flow Energy Dissipation in Sudden Contraction with Wall Roughness

Document Type : Research Article

Authors

1 Professor of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.

2 M.sc student, Department of civil engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.

Abstract

Introduction
One of the most important problems in hydraulic structures is the kinetic energy of the flow. If this destructive energy is not controlled, the structures downstream will be damaged and cause significant damage. One of the functions of energy dissipator structures is to change the flow regime, reduce the flow velocity and eliminate excess flow energy. One of the methods that can deplete the flow is to create a narrowing along with the roughness in the flow path. By creating a constriction in the flow path and using roughness in the constriction wall and forming a hydraulic jump, a significant part of the destructive energy of the flow can be dissipated. Hydraulic jump is a common phenomenon downstream of hydraulic structures that increases the flow depth by rapidly converting the flow from supercritical to subcritical and plays an important role in influencing hydraulic parameters. Examining previous studies on stenosis with natural wall roughness, what is certain is that no laboratory and numerical studies have been observed so far.
Methodology
A laboratory flume with a rectangular cross-section 5 meters long, 0.3 meters wide, 0.5 meters high, and with Plexiglas floors and walls was used to perform the experiments. Two pumps each with a capacity of 450 liters per minute enter the flow into the flume and the flow inlet flow is read by two rotameters with an error of ± 2%. A point gauge with an accuracy of one millimeter was used to measure the water depth, and a construction meter with an accuracy of one millimeter was used to measure the length of the jump length. To create narrowing in the cross section of the channel from glass boxes with a fixed height of 0.5 m, widths of 2.5, 5, 7.5 cm on each side and to create supercritical current upstream of the section Narrowing A valve with a width of 0.3 m, a thickness of 3 mm with an opening of 2 cm, which is located at a distance of 1.5 m from the narrowing, has been used.
Figure 1, schematic of the canal and the equipment installed on it and Figure 2, an example of stiffening placement, hydraulic jump formed in the flow path and rough placement method with three average diameters of 2.08, 1.28, 0.8 Shows centimeters on the wall.
Results and Discussion
In order to achieve the objectives of the present study, flow path constrictions have been provided using glass boxes and sand materials have been used to roughen the constriction walls. In total, 270 experiments were performed in the range of Froude number 2.5 to 7.5 and relative contraction range of 8.9 to 12.42. By adjusting the laboratory model and opening the pump, the flow enters the channel supercritically after passing through the vertical valve and moves towards the narrowing section.
As the downstream Froude number increases, the relative energy dissipation increases and this amount is greater than the energy dissipation in the constriction of 15 cm. The reason for this is that due to the collision of supercritical flow with the constriction section, the backwater profile at the point of water collision with the sides of the constriction elements and also the formation of hydraulic jump upstream of the constriction section increase turbulence and climate interference and consequently it increases the relative energy dissipation.
Changing the diameter of the rough particles has little effect on the amount of flow energy dissipation. But it can be seen that the effect of roughness with an average diameter of 1.28 cm is slightly more than other roughnesses. The reason for this is that the roughness of 1.28 cm has more contact surface with the flow and also the empty space between the grains increases the surface tension and shear stress. Therefore, some of the energy is wasted by hydraulic jumping and some of it is consumed by the backflow of the flow.
Conclusion
Comparison of the models with each other as a control showed that with increasing the amount of narrowing of the channel width, the relative energy consumption increases. According to laboratory results, the use of roughness significantly increases the relative energy consumption relative to the upstream. Energy dissipation in 15 cm constriction is 25.48%, 20.88% and 23.83% less than 0.8, 1.28 and 2.08 cm roughnesses in control mode, respectively. Energy dissipation in 10 cm constriction is less than 44.34, 43.68, and 40.63% in roughness compared to 0.8, 1.28, and 2.08 cm roughnesses, respectively. Energy dissipation at 5 cm constriction is 50.75, 51.19, and 40% less than 0.8, 1.28, and 2.08 cm roughnesses in control mode, respectively.

Keywords


Abbaspour, A., Hosseinzadeh Dalir, A. Farsadizadeh, D. and Sadraddini, A.A. (2009). Effect of sinusoidal corrugated bed on hydraulic jump characteristics. Journal of Hydro-Environment Research. 3(2), 109-117.
Badizadegan, R., Saneie, M. and Esmaili, K. (2014). Comparison of Hydraulic Jump Characteristics on Different Types of Corrugated Beds. Iran. J. Irrig. Drain. 8(2), 220-232.
Daneshfaraz, R., Aminvash, E. and Abbaszadeh, H. (2021d). Numerical Simulation of Energy Dissipation in Crescent-Shaped Contraction of the Flow Path. Iranian Journal of Soil and Water Research. 52(5), 1299-1314.
Daneshfaraz, R., Aminvash, E., Di Francesco, S., Najibi, A. and Abraham, J. (2021c). Three-Dimensional Study of the Effect of Block Roughness Geometry on Inclined Drop. Journal of Numerical Methods in Civil Engineering, 6(1), 1-9.
Daneshfaraz, R., Aminvash, E., Esmaeli, E., Sadeghfam, S. and Abraham, J. (2020). Experimental and numerical investigation for energy dissipation of supercritical flow in sudden contractions. Journal of Groundwater Science and Engineering. 8(4), 396-406.
Daneshfaraz, R., Aminvash, E., Ghaderi, A., Abraham, J. and Bagheradeh, M. (2021a). SVM Performance for Predicting the Effect of Horizontal Screen Diameters on the Hydraulic Parameters of a Vertical Drop. Applied Sciences, 11(9), 4238.
Daneshfaraz, R., Aminvash, E., Ghaderi, A., Kuriqi, A. and Abraham, J. (2021b). Three-Dimensional Investigation of Hydraulic Properties of Vertical Drop in the Presence of Step and Grid Dissipators. Symmetry. 13(5), 895.
Daneshfaraz, R., Kaya, B., Sadeghfam, S. and Sadeghi, H. (2014). Simulation of flow over ogee and stepped spillways and comparison of finite element volume and finite element methods. Journal of Water Resource and Hydraulic Engineering. 3(2), 37-47.
Daneshfaraz, R., Majedi Asl, M., Mirzaee, R. and Parsamehr, P. )2020(. Laboratory study of the effect of rough bed with non-continuous trapezoidal elements on hydraulic jump characteristics in non-prismatic rectangular channel. Sharif Journal Civil Engineering. 36.2(2.1), 119-128.  (In Persian)
Daneshfaraz, R., Rezazadeh Joudi, A. and Sadeghfam, S. (2018). Experimental Investigation of Energy Dissipation in the Sudden Choked Flow with Free Surfaces. Journal of Civil and Environmental Engineering. 48.2(91), 101-108. (In Persian)
Daneshfaraz, R., Rezazadeh Joudi, A. and Abraham, J. (2017). Numerical investigation on the effect of sudden contraction on flow behavior in a 90-degree bend. KSCE J. Civil Eng. 22, 603–612.
Daneshfaraz, R., Sadeghfam, S. and Mirzaeereza, R. (2019). Experimental Study of Expanding Effect and Sand-Roughened Bed on Hydraulic Jump Characteristics. Iranian Journal of Soil and Water Research. 50(4), 885-896. (In Persian)
Daneshfaraz, R., Sadeghfam, S. and Kashani, M. (2014). Numerical simulation of flow over stepped spillways. Research in Civil and Environmental Engineering, 2(04), 190-198.
Daneshfaraz, R., Sadeghi, H., Rezazadeh Joudi, A. and Abraham, J. (2017). Experimental investigation of hydraulic jump characteristics in contractions and expansions. Sigma Journal of Engineering & Natural Sciences. 35(1), 87-98.
Dey, S. and Raikar, R.V. (2007). Characteristics of horseshoe vortex in developing scour holes at piers. Journal of Hydraulic Engineering. 133(4), 399-413.
Elsebaie, I.H. and Shabayek, Sh. (2010). Formation of hydraulic jumps on corrugated beds. International Journal of Civil & Environmental Engineering. 10(01), 37-47.
Hager, W.H. and Dupraz, P.A. (1985). Discharge characteristics of local, discontinuous contractions. Journal of Hydraulic Res. 23(5), 421-433.
Izadjoo, F., Shafaei Bajestan, M., BINA, M. (2005). Hydraulic Jump Characteristics on A Trapezoidal Corrugated Bed. The Scientific Journal of Agriculture (SJA), 27, 107-122.
Jan, C.D. and Chang, C.J. (2009). Hydraulic jumps in an inclined rectangular chute contraction. Journal of Hydraulic Engineering. 135(11), 949-958.
Nasr Esfahani, M. and Shafaei Bejestan, M. (2012). Effect of Roughness Height on the Length of B jump at an Abrupt Drop. International Research Journal of Applied and Basic Sciences. 3, 2757-2762.
Nayebzadeh, B., Lotfollahi-yaghin, M. and Daneshfaraz, R. (2019). Experimental study of Energy Dissipation at a Vertical Drop Equipped with Vertical Screen with Gradually Expanding at the Downstream. Amirkabir Journal of Civil Engineering. 52(12), 7-7. (In Persian)
Nayebzadeh, B., Lotfollahi-yaghin, M. and Daneshfaraz, R. (2021). Numerical Investigation of Hydraulic Characteristics of Vertical Drops with Screens and Gradually Wall Expanding. Amirkabir Journal of Civil Engineering, 53(8), 4-4. (In Persian)
Neisi, K. and Shafai Bajestan, M. (2013). Characteristics of S-jump on Roughened Bed Stilling Basin. Journal of Water Sciences Research, 5(2), 25-34.
Pagliara, S., Carnacina, L. and Palermo, M, (2009). Energy dissipation in presence of block ramps with Enlarged stilling basins. pp.5042-5050. 33rd IAHR Congress, Water Engineering for a Sustainable Environment. 4-9 Aug. Vancouver, Canada.
Rahmanshahi Zahabi, M. and Shafai Bejestan, M. (2012). Experimental investigation of the effect of chute bed roughness height on energy dissipation. Journal of Water and Soil Science. 22(2), 96-101. (In Persian)
Rajaratnam, N. (1968). Hydraulic Jumps on Rough Beds, Trans. Engineering Inst. Canada, 11(a-2), 1-8.
Reinauer, R. and Hager, W.H. (1998). Supercritical flow in chute contraction. Journal of Hydraulic Engineering, 124(1), 55-6.
S‌a‌d‌e‌g‌h‌i, H., D‌a‌n‌e‌s‌h‌f‌a‌r‌a‌z, R., B‌e‌h‌m‌a‌n‌e‌s‌h, J. and Nikpou‌r, M. (2015). The effect of shape of walls of expansion on the characteristics of hydraulic jump. Sharif Journal of Civil Engineering. 31(2), 57-62.
Tokyay, N.D. (2005). Effect of channel bed corrugations on hydraulic jumps. EWRI. Water & Environmental Resources Congress. Anchorage. Alaska. USA. 8 p.
Tokyay, N.D., Evcimen, T.U. and Şimşek, C. (2011). Forced Hydraulic Jump on Nonprotruding Rough Beds. Can. J. Civil Eng. 38, 1136-1144.
Wu, B. and Molinas, A. (2001). Choked flows through short contractions. Journal of hydraulic Engineering. 127(8), 657-6 .62 
Yasuda, Y. and Hager Willi, H. (1995). Hydraulic jump in channel contraction. Canadian Journal of Civil Engineering. 22(5), 925-933
 
  • Receive Date: 14 June 2021
  • Revise Date: 19 July 2021
  • Accept Date: 02 August 2021
  • First Publish Date: 02 August 2021