Abstract
Rapidly varied open channel flows are characterized by curvilinear streamlines, thereby resulting in a pressure field different from the hydrostatic approach proposed in the standard gradually varied flow theory. This problem is related to environmental hydraulic problems such as the undular hydraulic jump and flow over round-crested weirs, for which streamline curvature effects are significant. The inclusion of the curvilinear streamline effect in an extended energy equation was firstly by Fawer. Most of the extended energy equations currently employed are therefore modified forms of the original Fawer approach. The aim of the present study is to highlight and remind engineers of the outstanding theory presented by Fawer. Herein, his approach for steady open channel flow with curved streamlines is revised and compared with experimental observations. Computational methods are presented in detail and based on present results, it can be observed that more recent and complex models for these problems are similar to the original proposal of Fawer, and hardly more accurate in some instances. Based on the proposed study an useful framework for theoretical models for steady open channel flows with curved streamlines is proposed.
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Abbreviations
- C d :
-
Discharge coefficient (–)
- F:
-
Froude number (–)
- g :
-
Acceleration of gravity (m2/s)
- H :
-
Total energy head (m)
- h :
-
Flow depth (m)
- h′:
-
dh/dx(−)
- h′:
-
d2 h/dx 2(m−1)
- h o :
-
Flow depth at approach flow section (m)
- h c :
-
Critical depth (m) = (q 2/g)1/3
- K :
-
Parameter (–)
- m :
-
Discharge coefficient (–)
- n :
-
Parameter (–)
- q :
-
Unit discharge (m2/s)
- L :
-
Wave amplitude (m)
- r :
-
Radius of curvature at channel bed (m)
- R :
-
Radius of curvature at free surface (m)
- R z :
-
Radius of curvature at elevation z (m)
- S :
-
Specific momentum (m2)
- S o :
-
Channel slope (–)
- S f :
-
Friction slope (–)
- U :
-
Depth-averaged velocity (m/s)
- V :
-
Magnitude of velocity vector (m/s)
- V s :
-
Free surface streamline velocity (m/s)
- x :
-
Streamwise coordinate (m)
- x o :
-
Streamwise position of approach flow section (m)
- y :
-
h/ho(−)
- z :
-
Elevation above channel bed (m)
- z b :
-
Elevation of channel bed (m)
- z b' :
-
dz b /dx(−)
- z b'' :
-
d2 z b /dx 2(m−1)
- ω :
-
Wave amplitude (m)
- η :
-
(h o/h c)3(−)
- φ :
-
Free surface angle with horizontal at reference section (°)
- φ z :
-
Angle of inclination of streamline with horizontal at distance z from channel bed (°)
- β :
-
Boussinesq momentum velocity coefficient (−)
- Δp z :
-
Pressure drop (m)
References
Chow VT (1959) Open channel hydraulics. McGraw-Hill, NewYork, NY
Montes JS (1998) Hydraulics of open channel flow. ASCE, Reston, VA
Boussinesq JV (1877) Essai sur la théorie des eaux courantes. Mémoires présentés par divers savants à l’Académie des Sciences, Paris, France, 23, 1–660; supplément 24, 1–60 (in French)
Fawer C (1937) Etude de Quelques Ecoulements Permanents à Filets Courbes. Thesis, Université de Lausanne, Imprimérie La Concorde, Lausanne, Switzerland (in French)
Ben meftah M, De Serio F, Mossa M, Pollio A (2007) Analysis of the velocity field in a large rectangular channel with lateral shockwave. Environ Fluid Mech 7(6): 519–536
Hager WH, Hutter K (1984) Approximate treatment of plane channel flow. Acta Mech 51(1–2): 31–48
Hager WH, Hutter K (1984) On pseudo-uniform flow in open channel hydraulics. Acta Mech 53(3–4): 183–200
Montes JS, Chanson H (1998) Characteristics of undular hydraulic jumps: experiments and analysis. J Hydraul Eng 124(2): 192–205
Castro-Orgaz O, Giráldez JV, Ayuso JL (2008) Higher order critical flow condition in curved streamline flow. J Hydraul Res 46(6): 849–853
Jaeger C (1956) Engineering fluid mechanics. Blackie, London
Serre F (1953) Contribution à l’étude des écoulements permanents et variables dans les canaux. La Houille Blanche 8(6–7):374–388; 8(12):830–887 (in French)
Matthew GD (1963) On the influence of curvature, surface tension and viscosity on flow over round-crested weirs. In: Proceedings of the institution of civil engineers, vol 25. London, England, pp 511–524. Discussion: 1964, 28:557–569
Hager WH (1985) Equations for plane, moderately curved open channel flows. J Hydraul Eng 111(3): 541–546
Matthew GD (1991) Higher order, one-dimensional equations of potential flow in open channels. In: Proceedings of the institution of civil engineers, vol 91. London, England, pp 187–201
Chanson H (1996) Free surface flows with near critical flow conditions. Can J Civ Eng 23(6): 1272–1284
Chanson H, Montes JS (1995) Characteristics of undular hydraulic jumps: experimental apparatus and flow patterns. J Hydraul Eng 121(2):129–144. Discussion: 1997, 123(2):161–164
Mandrup-Andersen V (1978) Undular hydraulic jump. J Hydraul Div ASCE 104(HY8):1185–1188. Discussion: 105(HY9):1208–1211
Montes JS (1986) A study of the undular jump profile. In: Proceedings of 9th Australasian fluid mechanics conference AFMC. Auckland, New Zealand, pp 148–151
Hager WH, Hutter K (1983) treatment of plane hydraulic jump with separation zone above the flow zone. J Hydraul Res 21(3): 195–204
Chanson H (2009) Development of the Bélanger equation and backwater equation by Jean-Baptiste Bélanger (1828). J Hydraul Eng 135(3): 159–163
Hager WH (1991) Experiments on standard spillway flow. In: Proceedings of the Institution of Civil Engineers, vol 90. London, England, pp 399–416
Montes JS (1970) Flow over round crested weirs. L’Energia Elettrica 47(3): 155–164
Hager WH (1985) Critical flow condition in open channel hydraulics. Acta Mech 54(3–4): 157–179
Chanson H (2006) Minimum specific energy and critical flow conditions in open channels. J Irrig Drain Eng 132(5): 498–502
Lenau CW (1967) Potential flow over spillways at low heads. J Eng Mech Div ASCE 93(3): 95–107
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Castro-Orgaz, O. Steady open channel flows with curved streamlines: the Fawer approach revised. Environ Fluid Mech 10, 297–310 (2010). https://doi.org/10.1007/s10652-009-9157-0
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DOI: https://doi.org/10.1007/s10652-009-9157-0