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HYDRAULICS. ENGINEERING HYDROLOGY. HYDRAULIC ENGINEERING

Account for the surface tension in hydraulic modeling of the weir with a sharp threshold

Vestnik MGSU 9/2014
  • Medzveliya Manana Levanovna - Moscow State University of Civil Engineering (MGSU) Candidate of Technical Sciences, Associate Professor, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 100-105

In the process of calculating and simulating water discharge in free channels it is necessary to know the flow features in case of small values of Reynolds and Weber numbers. The article considers the influence of viscosity and surface tension on the coefficient of a weir flow with sharp threshold. In the article the technique of carrying out experiments is stated, the equation is presented, which considers the influence of all factors: pressure over a spillway threshold, threshold height over a course bottom, speed of liquid, liquid density, dynamic viscosity, superficial tension, gravity acceleration, unit discharge, the width of the course. The surface tension and liquid density for the applied liquids changed a little. In the rectangular tray (6000x100x200) spillway with a sharp threshold was established. It is shown that weir flow coefficient depends on Reynolds number (in case Re < ~ 2000) and Webers number. A generalized expression for determining weir flow coefficient considering the influence of the forces of viscosity and surface tension is received.

DOI: 10.22227/1997-0935.2014.9.100-105

References
  1. Linford A. The Application of Models to Hydraulic Engineering – Reservoir Spillways. Water and Water Engineering. October, 1965, pp. 351—373.
  2. Engel F., Stainsby W. Weirs for Flow Measurement in Open Channels. Part 2. Water and Water Engineering. 1958, vol. 62, no. 747, pp. 190—197.
  3. Kindsvater C., Carter R. Discharge Characteristics of Rectangular Thin-plate Weirs. Transactions ASCE, 1957, vol. 122, pp. 772—822.
  4. Spronk R. Similitude des ecoulements Sur les deversoirs en mince paroi aux faibles charges. Rev. Univers. mines. 1953, vol. 3, no. 9, pp. 119—127.
  5. Hager W. Ausfluss durch vertikale offnungen. Wasser, Energ. Luft. 1988, vol. 80, no. 3—4, pp. 73—79.
  6. Al’tshul’ A.D., Medzveliya M.L. Ob usloviyakh otryva prilipshey strui na vodoslive s ostrym porogom [On the Conditions of Separating the Stuck Flood on the Weir with a Sharp Threshold]. Izvestiya vuzov: Stroitel’stvo [News of the Institutions of Higher Education]. 1991, no. 11, pp. 73—76.
  7. Medzveliya M.L., Pipiya V.V. Koeffitsient raskhoda vodosliva s shirokim porogom v oblasti malykh naporov [Discharge Ratio of the Broad-crested Weir Flow in the Low Head Area]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 4, pp. 167—171.
  8. Medzveliya M.L., Pipiya V.V. Usloviya obrazovaniya svobodnoy strui na vodoslive s ostrym porogom [Conditions of Formation of a Free Flow over a Sharp Crest Weir]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 1, pp. 185—189.
  9. Al’tshul’ A.D. Istechenie iz otverstiy zhidkostey s povyshennoy vyazkost’yu [Efflux of Liquids with Elevated Toughness]. Neftyanoe khozyaystvo [Oil Industry]. 1950, no. 2, pp. 55—60.
  10. Jameson A. Flow over Sharp-edged Weirs. Effect of Thickness of Crest . J. Inst. of Civil Engrs. Nov. 1948, vol. 31, no. 1, pp. 36—55. DOI: http://dx.doi.org/10.1680/IJOTI.1948.13377.
  11. D’Alpaos L. Sull’efflusso a stramazzo al di sopra di un bordo in parete sottile perpiccolshi valori del carico. Atti ist. Veneto sci lett. ed arti. Cl, sci mat. e natur. 1976—1977, vol. 135, pp. 169—190.
  12. Shchapov N.M. Gidrometriya gidrotekhnicheskikh sooruzheniy i gidromashin [Hydrometry of Hydraulic Engineering Structures and Hydraulic Units]. Moscow, Leningrad, Gosenergoizdat Publ., 1957, 235 p.
  13. Raju K.G.R., Asawa G.L. Viscosity And Surface Tension Effects On Weir Flow. J. of the Hydraulic Engineering, ASCE. 1977, vol. 103, no. 10, pp. 1227—1231.
  14. Rosanov N., Rosanova N. Some Problems of Modeling Water Outlet Structures with Free — Surface Flow. Proc. 19 IAHR congr. New-Delhi, 1981, vol. 5, pp. 81—91.
  15. Molitor D.A. Hydraulics of Rivers, Weirs and Sluices. 1st ed. New York : John Wiley & Sons; London : Chapman & Hall, Limited. 1908. 178 p.

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The coefficient of discharge in a channel with side narrowing

Vestnik MGSU 6/2015
  • Medzveliya Manana Levanovna - Moscow State University of Civil Engineering (MGSU) Candidate of Technical Sciences, Associate Professor, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 110-114

The author considers the influences of the forces of viscosity and superficial tension on the discharge ratio in a channel with side narrowing. In the article the equation is presented that takes into account the influence of all the factors: the pressure, the speed of the liquid, liquid density, dynamic viscosity, superficial tension, gravity acceleration, expense per unit of width, width of the course, width of narrowing. Superficial tension and liquid density for the used liquids changed a little.The narrowing in the rectangular tray was achieved by force of flowing liquid between rectangular parallelepipeds, which were attached to the wall of the tray. The dimensions of the rectangular parallelepipeds were: the length L = 200 mm, the width B = 33 mm, and the depth of the mouth b = 34 mm.The findings of the experiment proved that the increase in the Reynolds number causes the increase flow discharge ratio and it approaches the constant value at Re ? 4000.

DOI: 10.22227/1997-0935.2015.6.110-114

References
  1. Kabiri-Samani A.R., Shams M.-R. Discharge Coefficient of Subsurface Weirs. Proceedings of the Institution of Civil Engineers. Water Management. 2014, vol. 167, no. 4, pp. 187—193. DOI: http://dx.doi.org/10.1680/wama.12.00050.
  2. Ramamurthy A.S., Kai J., Han S.S. V-Shaped Multislit Weirs. Journal of Irrigation and Drainage Engineering. 2013, vol. 139, no. 7, pp. 582—585. DOI: http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000574.
  3. Aydin I., Ger A.M., Hincal O. Measurement of Small Discharges in Open Channels by Slit Weir. Journal of Hydraulic Engineering. 2002, vol. 128, no. 2, pp. 234—237. DOI: http://dx.doi.org/10.1061/(ASCE)0733-9429(2002)128:2(234).
  4. Ranga Raju K.G., Srivastava R., Porey P.D. Scale Effects in Modelling Flow over Broad-Crested Weirs. Irrigation & Power. 1990, vol. 47, no. 30, pp. 101—106.
  5. Roche N., Daïan J.-F., Lawrence D.S.L. Hydraulic Modeling of Runoff over a Rough Surface under Partial Inundation. Water Resources Research. 2007, vol. 43, no. 8. W08410, pp. 1—11. DOI: http://dx.doi.org/10.1029/2006wr005484.
  6. Raju R., Asawa L. Viscosity and Surface Tension Effects on Weir Flow. J. of the Hydraulics div. ASCE. 1977, vol. 103, no. 10, pp. 1227—1231.
  7. Raju R., Ali J., Ahmad J. Discharge Relationship for Suppressed and Contracted. Thin-plate Weirs. J. of the Inst. of Engnrs. India. 1972, vol. 52, no. 11, pp. 286—293.
  8. Zhang K., Wang G., Sun X., Yang F., Lü H. Experiment on Hydraulic Characteristics of Shallow open Channel Flow on Slope. Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering. 2014, vol. 30, no. 15, pp. 182—189. DOI: http://dx.doi.org/10.3969/j.issn.1002-6819.2014.15.024.
  9. Maxwell W., Hall C., Weggel J. Surface Tension in Froude Models. J. of Hydraulics Division. ASCE. 1969, vol. 95, no. HY2, March, pp. 677—704.
  10. Milano V. Ricerca sperimentale sull eflusse di cerenti lente au stramazzi in parete sottile a bassa soglia. Idrotecnica. 1981, no. 6, pp. 263—274.
  11. Linford A. The Application of Models to Hydraulic Engineering — Reservoir Spill-ways. Water and Water Engn. Oct. 1965, pp. 411—417.
  12. Medzveliya M.L., Pipiya V.V. Usloviya obrazovaniya svobodnoy strui na vodoslive s ostrym porogom [Conditions of Formation of a Free Flow over a Sharp Crest Weir]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 1, pp. 185—189. (In Russian)
  13. Al’tshul’ A.D. Istechenie iz otverstiy zhidkostey s povyshennoy vyazkost’yu [Outflows of Hyperviscosity Liquids through Holes]. Neftyanoe khozyaystvo [Crude Oil Economy]. 1950, no. 2, pp. 55—60. (In Russian)
  14. Medzveliya M.L., Pipiya V.V. Koeffitsient raskhoda vodosliva s shirokim porogom v oblasti malykh naporov [Discharge Ratio of the Broad-crested Weir Flow in the Low Head Area]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 4, pp. 167—171. (In Russian)
  15. Medzveliya M.L. Uchet poverkhnostnogo natyazheniya pri gidravlicheskom modelirovanii vodosliva s ostroy kromkoy [Account for the Surface Tension in Hydraulic Modeling of the Weir with a Sharp Threshold]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2014, no. 9, pp. 100—105. (In Russian)

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