Abstract
This paper describes an imaging method for measuring water surface in rapidly varying flows based on light absorption. After preliminary spatially distributed calibration, the water depth field is obtained by processing the images of the free surface captured by a digital camera looking downstream at a back-lighted device. The water body is coloured so that it acts as a variable-density filter. This method was used to detect the topography of water surface in a series of laboratory dam-break tests. Its validity was assessed by locally comparing the water depth time series derived from images with the ones returned by six ultrasonic distance metres. The experimental results obtained starting from two different image formats show that the accuracy of this technique is comparable to that of conventional ultrasonic transducers. Therefore, the method can be considered as an effective tool for collecting high-resolution spatial distributed experimental data useful to validate numerical models.
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References
Aureli F, Mignosa P, Tomirotti M (2000) Numerical simulation and experimental verification of dam-break flows with shocks. J Hydraul Res 38(3):197–205
Aureli F, Maranzoni A, Mignosa P, Ziveri C (2008) Dam-break flows: acquisition of experimental data through an imaging technique and 2D numerical modeling. J Hydraul Eng 134(8):1089–1101
Barter JD, Beach KL, Lee PHY (1993) Collocated and simultaneous measurement of surface slope and amplitude of water waves. Rev Sci Instrum 64(9):2661–2665
Bateman A, Granados A, Medina V, Nalesso M, Velasco D (2006) Experimental procedure to obtain 2D time-space high-speed water surface. In: Ferreira R, Alves E, Leal J, Cardoso A (eds) River flow 2006. Taylor & Francis, London, pp 1879–1888
Bechteler W, Kulisch H, Nuijc M (1992) 2-D dam-break flooding waves: comparison between experimental and calculated results. In: Proceedings of 3rd international conference on floods and flood management, Florence, Italy, pp 247–260
Bell S, Elliot R, Chaudhry MH (1992) Experimental results of two-dimensional dam-break flows. J Hydraul Res 30(2):225–252
Bellos CV, Soulis JV, Sakkas JG (1992) Experimental investigation of two-dimensional dam-break induced flows. J Hydraul Res 30(1):47–63
Braschi G, Dadone F, Gallati M (1994) Plain flooding: near field and far field simulations. In: Molinaro P, Natale L (eds) Modelling of flood propagation over initially dry areas. ASCE, New York, pp 45–59
Capart H, Young DL (1998) Formation of a jump by the dam-break wave over a granular bed. J Fluid Mech 372:165–187
Cochard S, Ancey C (2008) Tracking the free surface of time-dependent flows: image processing for the dam-break problem. Exp Fluids 44(1):59–71
Dabiri D (2009) Digital particle image thermometry/velocimetry: a review. Exp Fluids 46(2):191–241
Eaket J, Hicks FE, Peterson AE (2005) Use of stereoscopy for dam break flow measurement. J Hydraul Eng 131(1):24–29
Evans AJ (2010) Laser scanning applied to hydraulic modeling. International archives of photogrammetry. Remote sensing and spatial information sciences 38(5):224–227
Fraccarollo L, Toro EF (1995) Experimental and numerical assessment of the shallow water model for two-dimensional dam-break type problems. J Hydraul Res 33(6):843–864
Grant I, Zhao Y, Smith GH, Stewart JN (1995) Split-screen, single-camera, laser-matrix, stereogrammetry instrument for topographical water wave measurements. Appl Opt 34(19):3806–3809
Huang MYF, Huang AYL, Capart H (2010) Joint mapping of bed elevation and flow depth in microscale morphodynamics experiments. Exp Fluids. doi:10.1007/s00348-010-0858-4
Irish JL, Lillycrop WJ (1999) Scanning laser mapping of the coastal zone: the SHOALS system. ISPRS J Photo Rem Sens 54(2–3):123–129
Jähne B, Klinke J, Waas S (1994) Imaging of short ocean wind waves: a critical theoretical review. J Opt Soc Am A 11(8):2197–2209
Jähne B, Schmidt M, Rocholz R (2005) Combined optical slope/height measurements of short wind waves: principle and calibration. Meas Sci Technol 16(10):1937–1944
Kraus K (1997) Photogrammetry. Dummler, Bonn
Kurata J, Grattan KTV, Uchiyama H, Tanaka T (1990) Water surface measurement in a shallow channel using the transmitted image of a grating. Rev Sci Instrum 61(2):736–739
Lauber G, Hager WH (1998a) Experiments to dambreak wave: horizontal channel. J Hydraul Res 36(3):291–307
Lauber G, Hager WH (1998b) Experiments to dambreak wave: sloping channel. J Hydraul Res 36(5):761–773
Lee C, Wu CH, Hopes JA (2009) Simultaneous particle size and concentration measurements using a back-lighted particle imaging system. Flow Meas Instr 20(4–5):189–199
Moisy F, Rabaud M, Salsac K (2009) A synthetic Schlieren method for the measurement of the topography of a liquid interface. Exp Fluids 46(6):1021–1036
Morris MW (2000) CADAM: Concerted action on dambreak modelling. Final report, EC report SR 571, Wallingford
Morris M (2005) IMPACT: investigation of extreme flood processes and uncertainty. Final technical report, Wallingford. http://www.impact-project.net
Nitsche W, Dobriloff C (eds) (2009) Imaging measurement methods for flow analysis. Springer, Berlin
Pearson RK (1999) Data cleaning for dynamic modelling and control. In: Proceedings of European control conference, Karlsruhe, Germany
Roesgen T, Lang A, Gharib M (1998) Fluid surface imaging using microlens arrays. Exp Fluids 25(2):126–132
Soares-Frazão S (2007) Experiments of dam-break wave over a triangular bottom sill. J Hydraul Res 45(Suppl 1):19–26
Soares-Frazão S, Zech Y (2008) Dam-break flow through an idealised city. J Hydraul Res 46(5):648–658
Wyszecki G, Stiles WS (1982) Color science: concepts and methods, quantitative data and formulae. Wiley, New York
Zhang X, Cox CS (1994) Measuring the two-dimensional structure of a wavy water surface optically: a surface gradient detector. Exp Fluids 17(4):225–237
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Aureli, F., Maranzoni, A., Mignosa, P. et al. An image processing technique for measuring free surface of dam-break flows. Exp Fluids 50, 665–675 (2011). https://doi.org/10.1007/s00348-010-0953-6
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DOI: https://doi.org/10.1007/s00348-010-0953-6