Effect of the physical properties of a liquid on discharge coefficient in case of efflux from under the gate
Pages 147-152
Hydraulic engineering models are usually calculated according to Fraud law. Though in the process of small size models operation also viscosity and service tension forces become essential and we can’t neglect them.
The article considers the influence of viscosity and surface tension on discharge coefficient in case of efflux from under the gate. In the article the technique of carrying out experiments is stated, the equation is presented, which considers the influence of all factors: pressure, speed of liquid, liquid density, dynamic, superficial tension, gravity acceleration, unit discharge, width of the course, opening height. The surface tension and the liquid density for the used liquids changed a little. The gate was established in a rectangular trough (6000×100×200).
It is shown that with the increase of Reinolds number (at a relative opening a/H = 00,04…0,03 and Webers number
We > 250) the discharge coefficient rises and no longer depends on the Reinolds number, at Re > 2000 and Webers number (at constant values of Reinolds numbers) practically does not influence the discharge coefficient.
DOI: 10.22227/1997-0935.2014.10.147-152
- Allen J. Scale Models in Hydraulic Engineering. London, Longmens Green, 1947, 440 p.
- Benedini M. Lo stramazzo Bazin in canali di grandi dimensioni. Energia electr., 1966, vol. 43, no. 7, pp. 412—423.
- Maxwell W., Hall C., Weggel J. Surface Tension in Froude Models. J. of Hydraulics Division, ASCE. 1969, vol. 95, no. 2, pp. 677—704.
- Martynov I.P. Istechenie iz-pod ploskogo shchita [Efflux from under Flat Panel]. Nauchnye zapiski Moskovskogo gidromeliorativnogo instituta im. Vil'yamsa [Proceedings of Moscow Hydrotechnological Institute Named after Williams]. 1959, vol. 21, pp. 263—272. (in Russian)
- 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.
- D’Alpaos L. Sull’efflusso a stramazzo al di sopra di un bordo in parete s ottile per piccolo Valori del carico. Atti ist.Veneto sci lett. ed arti. Cl, sci mat. e natur. 1976—1977, vol. 135, pp. 169—190.
- 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)
- Linford A. The Application of Models to Hydraulic Engineering — Reservoir Spillways. Water and Water Engn. Oct. 1965, pp. 351—373.
- Engel F.V.A., Stainsby W. Weirs for Flow Measurement in Open Channels. Part 2. Water and Water Engng. 1958, vol. 62, no. 747, pp. 190—197.
- Raju R., Asawa G.L. Viscosity and Surface Tension Effects on Weir Flow. J. of the Hydraulics Div., ASCE. 1977, vol. 103, no. 10, pp. 1227—1231.
- Lenz A.T. Viscosity and Surface Tension Effects on V-Notch Weir Coefficients. Transactions, ASCE. 1943, vol. 108, no. 1, pp. 351—373.
- Al'tshul' A.D. Istechenie iz otverstiy zhidkostey s povyshennoy vyazkost'yu [Efflux of the Liquids with Raised Viscosity from the Holes]. Neftyanoe khozyaystvo [Oil Industry]. 1950, no. 2, pp. 55—60. (in Russian)
- 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. (in Russian)
- 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)
- Rel'tov B.F. Ob istechenii iz-pod vertikal'nogo shchita v gorizontal'nyy lotok [On the Efflux from under Vertical Gate into Horizontal Triugh]. Izvestiya VNIIG [News of All-Russian Scientific and Research Institute of Hydraulic Engineering]. 1934, vol. 11, no. 23, pp. 29—41. (in Russian)