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بررسی آزمایشگاهی مقایسه اثر صفحه متخلخل، مانع پیوسته و مانع متخلخل پیوسته در لبه سرریز پلکانی بر مشخصههای جریان | ||
| تحقیقات مهندسی سازه های آبیاری و زهکشی | ||
| دوره 22، شماره 83، مرداد 1400، صفحه 121-140 اصل مقاله (1.57 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22092/idser.2021.354709.1473 | ||
| نویسندگان | ||
| سید امین اصغری پری* 1؛ مجتبی کردناییج2 | ||
| 1دانشیار گروه عمران دانشگاه صنعتی خاتم الانبیاء بهبهان، ایران | ||
| 2مدرس گروه عمران دانشگاه صنعتی خاتم الانبیاء بهبهان، ایران | ||
| چکیده | ||
| در تحقیق حاضر به بررسی اثر مانع پیوسته و متخلخل و صفحه متخلخل با ارتفاعهای مختلف در لبه سرریز پلکانی بهمنظور شناخت مشخصات جریان پرداخته شده است. آزمایشها بر روی سرریز پلکانی با دو شیب 1:3 و 1:2، ارتفاع پله 9/10 سانتیمتر، طول پلههای 3/31 و 9/20 و عرض فلوم 2/1 متر انجام گردید. برای اندازهگیری پارامترهای جریان از عمقسنج با دقت 1± میلیمتر و تکنیک BIV استفاده گردید. نتایج نشان میدهد که محل هواگیری طبیعی در حالتیکه مانع پیوسته در لبه پله قرار گیرد نسبت به حالت شاهد در هر دو شیب یک پله بهسمت پاییندست حرکت میکند. بر اساس نتایج پردازش تصویر و استهلاک انرژی، در مواردی که ناحیه اختلاط و ناحیه برگشتی جریان افزایش یابد، میزان استهلاک انرژی افزایش مییابد. از بین موانع استفاده شده در تحقیق حاضر صفحه متخلخل بهدلیل دارای بودن ناحیه اختلاط بیشتر و همچنین امکان عبور جت آب از داخل تخلخلها، بیشترین میزان استهلاک انرژی را نسبت به مانع متخلخل و مانع پر داشته است و این مقدار نسبت به حالت شاهد در هر دو شیب نیز بیشتر بوده است. همچنین میزان استهلاک انرژی در شیب 1:3 در تمامی آزمایشها بیشتر از شیب 1:2 بوده است. | ||
| کلیدواژهها | ||
| استهلاک انرژی؛ سرریز پلکانی؛ صفحه متخلخل؛ مانع پیوسته؛ مانع متخلخل | ||
| عنوان مقاله [English] | ||
| Laboratory examination of Comparison of the effect of the porous screen,, continuous obstacle, and continuous porous obstacle on the edge of a stepped spillway | ||
| نویسندگان [English] | ||
| Seyed Amin Asghari Pari1؛ Mojtaba Kordnaeij2 | ||
| 1Associated professor of civil engineering/Behbahan Khatam Alanbia university of technology, Behbahan, Iran. | ||
| 2Graduated M.S.c. / Behbahan Khatam Alanbia University of Technology. | ||
| چکیده [English] | ||
| Extended Abstract Introduction Step chutes as a structure are commonly used in earth dams and weighted concrete dams (Chanson, 2001). The presence of a step in the spillway acts like a roughness compared to a smooth chute, which causes the amount of air to enter and as a result, the amount of energy dissipation in the direction of the spillway step increases. In recent decades, extensive research, often laboratory-oriented, has been conducted by researchers to identify the type of flow, the effect of step dimensions, the onset of aeration, and the mechanism of energy dissipation. Further research has attempted to place continuous and discontinuous obstacles and roughness at the bottom of the steps in Floors and edges of step with a variety of shapes and arrangements, deformation of steps, creating angles along the spillway, creating angles in the floor of the steps and edge obstacle, artificial aeration in the steps investigated the hydraulic conditions. In general, in some cases, depending on the height of the obstacle used, the slope of the spillway, the outlet flow, the type of obstacles and the location of the obstacle, the depreciation effect has been positive or negative. Methodology The flume used was direct, with a length of 10 m, a width of 1.2 m and a height of 1.2 m in the first 2 m, and 1 m in length of the flume with maximum flow rate 150 liters per second. Measurement of water depth in the tail-water and upstream was carried out using a point gage with an accuracy of ± 1 mm. The spillway have 8 steps, where the vertical length of step (h) is 10.9 cm, the horizontal length of step (L) is 31.3 cm, and the total height is 87 cm, while at a 1:2 slope, the length of step is 20.9 cm and the total height is 88 cm. The image was recorded by Sony FS5 camera with 240 frames per and second, along with 3 LED150 projectors. Results and Discussion In the 1: 3 slope in the transition regime, the obstacles used had a positive dissipation effect compared to the flat step. In this slope and flow regime, the porous obstacle (EP) has a greater dissipation effect than the porous screen (ES) and the full obstacle (EO), respectively, and in all three expressed arrangements (EO, ES, EP) in this regime the relative height of 0.38 had the highest dissipation rate. The superiority of the porous obstacle in this regime in energy dissipation is due to the three-dimensionality of the porous obstacle, which depletes the flow energy. Then in the procedure regime for 1: 3 slope, the results show that all three arrangements used have increased energy dissipation compared to the flat step, in this case, respectively, porous screen (ES), porous obstacle (EP) and full obstacle (EO), respectively. Had the highest energy consumption. For example, at the maximum flow rate, the flat steep energy dissipation rate is 46%, which is 55% for the porous screen (ES), 52% for the porous obstacle (EP) and 49% for the full obstacle (EO). Conclusions The present study compares the use of continuous obstacle, porous obstacle (3 dimensional) and screen obstacle (2 dimensional) with three heights at the edge of the step at two slopes of 1: 3 and 1: 2 in all three flows regime of nappe, transitional, and skimming. 1- The placement of continuous obstacle with different shape (filled continuous, porous obstacle and screen obstacle) at the edge of spillway for both slopes of this research causes the onset of the flow regime shift to the flat step and start of the inception point of free aeration (IP) was transmitted to a lower step toward the downstream relative to flat step on both slopes of the present research. 2- Based on the BIV results and a comparison of energy dissipation, it can be stated that continuous obstacles that can expand the mixing zones (including MZ and RF) increase energy dissipation. In fact, the recirculation zone has less dissipation effect than the mixing zone. 3- The creation of a porous obstacle and a porous screen on both slopes has increased energy dissipation compared to the full obstacle in all three flow regimes. This effect will increase with increasing the relative height of the obstacle until it reaches the pool (RZp) on the steps. Keywords: Energy dissipation, BIV Technique, Step spillway, Screen obstacle, Continous obstacle, Porous obstacle. | ||
| کلیدواژهها [English] | ||
| Energy dissipation, Step spillway, Screen obstacle, Continous obstacle, Porous obstacle | ||
| مراجع | ||
|
Ali, A. S., & Yousif, O. S. Q. (2019, October). Characterizations of flow over stepped spillways with steps having transverse slopes. In IOP Conference Series: Earth and Environmental Science (Vol. 344, No. 1, p. 012019). IOP Publishing.
Amador, A., Sanchez-Juni M, Dolz J. (2006). Characterization of the non-aerated flow region in a stepped spillway by PIV. J Fluid Eng ASME 138(6):1266–1273.
Asghari Pari, S. A, Kordnaeij, M. (2019). Investigating the Effect of eliminate of lateral discontinuous Obstacle on the Stepped Spillway on Flow Characteristics with image processing. 18th Iranian Hydraulic Conference. Tehran, Iran. (In Persian)
Asghari Pari, S. A, Kordnaeij, M. (2021). Investigating the Effect of Different Arrangements of Obstacle on the Stepped Spillway on Flow Characteristics and Energy Dissipation. Irrigation Sciences and Engineering, 43(4), 33-49. doi: 10.22055/jise.2021.36213.1940
Ashoor, A., & Riazi, A. (2019). Stepped Spillways and Energy Dissipation: A Non-Uniform Step Length Approach. Applied Sciences, 9(23), 5071.
Boes, R. M. and Hager, W.H. (2003a). Hydraulic design of stepped spillways. Journal of Hydraulic Engineering, 129(9), 671-679.
Boes, R. M. and Hager, W.H. (2003b). Two-Phase flow characteristics of stepped spillways. Journal of Hydraulic Engineering, 129(9), 661-670.
Bühler, P., Leandro, J., Bung, D., Lopes, P. and Carvalho, R. (2015). Measuring void fraction of a stepped spillway with non-intrusive methods using different image resolutions. IWHS 2015, 41.
Bung D and Valero D. (2015). Image Processing for Bubble Image Velocimetry in self Aerated Flow, 36th IAHR World Congress, 28 June – 3 July, Huge, Netherland.
Bung, D. B. (2013). Non-intrusive detection of air-water surface roughness in self-aerated chute flows. Journal of Hydraulic Research, 51(3), 322–329.
Bung, D.B. (2011). Developing flow in skimming flow regime on embankment stepped spillways. Journal of Hydraulic Research, 49(5), 639–648.
Bung, D.B. and Schlenkhoff, A. (2010). Self-aerated skimming flow on embankment stepped spillways: the effect of additional micro-roughness on energy dissipation and oxygen transfer. Proceedings of 1 st European IAHR Congress, Edinburgh, Flash-drive.
Chang K-A and Liu P L-F. (1998). Velocity, acceleration and vorticity under a breaking wave. Phys. Fluids 10 327–9.
Chanson, H. (1995). Hydraulic design of stepped cascades, channels, weirs and spillways.
Chanson, H. (2001). Hydraulic design of stepped spillways and downstream energy dissipators. Dam Engineering, 11(4), 205-242
Chanson, H. (2001). A transition flow regime on stepped spillways: the facts In: Proceedings of the 29 The IAHR Congress. Beijing, China, Pp: 490-498.
Chanson, H., Bung, D. B., & Matos, J. (2015). Stepped spillways and cascades. IAHR Monograph. School of Civil Engineering, University of Queensland, Brisbane, Australia.
Emadzadeh, A. CHiew, Y. M. (2017). Bubble Dynamics and PIV Measurements in a Hydraulic Jump. The 37th IAHR World Congress August 13 – 18, Kuala Lumpur, Malaysia.
Felder, S and Chanson, H. (2014). Effects of Step Pool Porosity upon Flow Aeration and Energy Dissipation on Pooled Stepped Spillways. Journal of Hydraulic Engineering, ASCE, Vol.140, No. 4, Paper 04014002, 11 pages.
Felder, S., & Chanson, H. (2015). Simple design criterion for residual energy on embankment dam stepped spillways. Journal of Hydraulic Engineering, 142(4), 04015062.
Frizell, K. W., Renna, F. M., and Matos, J. (2013). Cavitation potential of flow on stepped spillways. J. Hydraulic. Eng., 10.1061/(ASCE)HY.1943-7900.0000715, 630–636.
Goepfert, C., Marié, J. L. and Lance, M. (2004). Characterizing of an experimental device generating homogeneous and Isotropic turbulence by synthetic jets. The 9 th French Congress of Laser Velocimetry. ULB. Sept.14-17. Brussels. Belgium. (In French)
Gonzalez, C. A., & Chanson, H. (2007). Hydraulic design of stepped spillways and downstream energy dissipators for embankment dams. Dam Engineering, 17(4), 223-244.
Guenher, P., Felder, S., and Chanson, H. (2013). Flow Aeration, Cavity Processes and Energy Dissipation on Flat and Pooled Stepped Spillways for Embankments." Environmental Fluid Mechanics, Vol. 13, No. 5, pp. 503-525 (DOI: 10.1007/s10652-013-9277-4).
Habibi, K, Asghari Pari, S. A, Kordnaeij, M. (2021). Experimental investigating of the Effect of location of discontinuous Obstacle on the Stepped Spillway on Flow Characteristics with image processing. 19th Iranian Hydraulic Conference. Mashhad, Iran. (In Persian)
Hamedi, A., Mansoori, A., Shamsai, A., & Amirahmadian, S. (2014). Effects of End Sill and Step Slope on Stepped Spillway Energy Dissipation. J. Water Sci. Res, 6(1), 1.
Hunt, S. L., and Kadavy, K. C. (2010). “Energy dissipation on flat-sloped stepped spillways: Part 1. Upstream of the inception point.” Trans. ASABE, 53(1), 103–109.
Hussein, B. S. and S. A. Jalil. (2016). Hydraulic Comparison between Labyrinth and Plain Stepped Falls. Journal of University of Duhok, Vol. 19, No.1 (Pure and Eng. Sciences), Pp
Kordnaeij, M., Asghari Pari, S., Sajjadi, S., Shafai Bajestan, M. (2017). Experimentally Comparisons of the Effect of Porous Sheets and 3D-Porous Obstacles in Controlling Turbidity Current. Water and Soil Science, 27(1), 43-54. (In Persian)
Kordnaeij, M, Asghari Pari, S. A. (2019). Experimental Investigating the Effect continuous Obstacle on the edge of Stepped Spillway on Flow Characteristics with image processing (BIV). 11th international River Engineering Conference, Ahwaz, Iran. (In Persian)
Kökpinar, M. A. (2004). Flow over a stepped chute with and without macro-roughness elements. Canadian Journal of Civil Engineering, 31(5), 880-891.
Kramer, M and Chanson, H. (2018). Transition flow regime on stepped spillways: air–water flow characteristics and step-cavity fluctuations, Environ Fluid Mech .https://doi.org/10.1007/s10652-018-9575-y.
Leandro, J., Bung, D.B. & Carvalho, R. (2014). Measuring void fraction and velocity fields of a stepped spillway for skimming flow using non-intrusive methods. Exp Fluids
Lopes, P., Leandro, J., Carvalho, R. F., & Bung, D. B. (2017). Alternating skimming flow over a stepped spillway. Environmental Fluid Mechanics, 17(2), 303-322.
Meireles, I. and Matos, J. (2009). Skimming flow in the non-aerated region of stepped spillways over embankment dams. Journal of Hydraulic Engineering, 135(8), 685-689.
Mero, S., & Mitchell, S. (2017). Investigation of energy dissipation and flow regime over various forms of stepped spillways. Water and environment journal, 31(1), 127-137.
Novakoski, C. K., Ferla, R., Prá, M. D., Canellas, A. V. B., Marques, M. G., & Teixeira, E. D. (2020). Stepped spillway with pre-aeration by a deflector: flow characteristics. RBRH, 25.
Ostad Mirza, M. J. (2016). Experimental study on the influence of abrupt slope changes on flow characteristics over stepped spillways (No. THESIS). EPFL.
Ostad Mirza, M. J., Matos, J., Pfister, M., & Schleiss, A. J. (2016). Effect of an abrupt slope change on air entrainment and flow depths at stepped spillways. Journal of Hydraulic Research, 55(3), 362-375.
Razmkhah, A, Asghari Pari, S. A, Kordnaeij, M. (2021). Experimental investigating of the Effect of location of continuous Obstacle on the Stepped Spillway on Flow Characteristics with image processing. 19th Iranian Hydraulic Conference. Mashhad, Iran. (In Persian)
Ryu Y., Chang KA. and Lim HJ. (2005). Use of bubble image velocimetry for measurement of plunging wave impinging on structure and associated green water, Meas. Sci. Technol., 16(10), 1945-1953.
Takahashi, M, Gonzalez, CA., Chanson, H. (2006). Self-aeration and turbulence in a stepped channel Influence of cavity surface roughness. International Journal of Multiphase Flow, 32, 1370–1385.
Thielicke, W and Stamhuis, E J. (2014). PIVlab – Towards User-friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB. Journal of Open Research Software, 2: e30, DOI: http://dx.doi.org/10.5334/jors.bl.
Torabi, H., Parsaie, A., Yonesi, H., & Mozafari, E. (2018). Energy dissipation on rough stepped spillways. Iranian Journal of Science and Technology, Transactions of Civil Engineering, 42(3), 325-330.
Wright, H. J. (2010, May). Improved energy dissipation on stepped spillways with the addition of triangular protrusions. In 78th ICOLD Annual Meeting, Hanoi.
Zare, H. K., & Doering, J. C. (2012). Energy dissipation and flow characteristics of baffles and sills on stepped spillways. Journal of hydraulic research, 50(2), 192-199.
Zhang, G., & Chanson, H. (2018). Air-water flow properties in stepped chutes with modified step and cavity geometries. International Journal of Multiphase Flow, 99, 423-436. 55: 1732. https://doi.org/10.1007/s00348-014-1732-6. | ||
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