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Measurement by Free-Surface Synthetic Schlieren of the topography of a liquid interface


F. Moisy, M. Rabaud


We have developed an optical method for the measurement of the instantaneous topography of the interface between two transparent fluids, named Free-Surface Synthetic Schlieren, or FS-SS (Moisy et al, 2009). This method is based on the analysis of the refracted image of a random dot pattern visualized through the interface. The apparent displacement field between the refracted image and a reference image obtained when the surface is flat is determined using a Digital Image Correlation algorithm. A numerical integration of this displacement field, based on a least square inversion of the gradient operator, is used for the reconstruction of the instantaneous surface height, allowing for an excellent spatial resolution with a low computational cost. The main limitation of the method, namely the ray crossing (caustics) due to strong curvature and/or large surface-pattern distance, is discussed.

A tutorial for implementing a FS-SS system under Windows is available here.


A plane wave generated by an oscillating plate.

Wake pattern generated by the translation of a small obstacle (comparison experiment / numerics).

Movie of the circular wave created by the impact of a drop (Acquisition rate 100 Hz).

Movie of the spreading of a silicon oil drop on a transparent substrate.

3D reconstruction of a cross-wave, generated by the vertical oscillation of a fully immersed wavemaker. What are cross-waves?.

Publications

  • Surface deformations and wave generation by wind blowing over a viscous liquid
    A. Paquier, F. Moisy, and M. Rabaud, Phys. Fluids 27, 122103 (2015)
    [Abstract | PDF]
  • Crosswaves induced by the vertical oscillation of a fully immersed vertical plate
    F. Moisy, G.-J. Michon, M. Rabaud, E. Sultan, Phys. Fluids 24, 022110 (2012).
    [Abstract | PDF | movies]
  • Estimation des corrections non-linéaires dans la méthode FS-SS de mesure optique de la surface d’un liquide transparent
    M. Rabaud, F. Moisy, 20ème Congrès Français de Mécanique, 29 août - 2 septembre 2011, Besançon.
    [PDF]
  • Unpredictable tunneling of a classical wave-particle association
    A. Eddi, E. Fort, F. Moisy, Y. Couder, Phys. Rev. Lett. 102, 240401 (2009).
    [Abstract]
  • A Synthetic Schlieren method for the measurement of the topography of a liquid interface
    F. Moisy, M. Rabaud, K. Salsac, Exp. in Fluids 46 (6), 1021-1036 (2009).
    [PDF]
  • Measurement by Digital Image Correlation of the topography of a liquid interface
    F. Moisy, M. Rabaud, E. Pinsolle, ISFV13 - 13th International Symposium on Flow Visualization, and FLUVISU12 - 12th French Congress on Visualization in Fluid Mechanics, Paper #326, July 1-4, 2008, Nice (2008).
    [PDF]
  • Optical measurement of ship waves by Digital Image Correlation
    M. Rabaud, F. Moisy, International Conference on Innovation in High Performance Sailing Yachts, 29-30 May 2008, Lorient, France, ISBN 978-1-905040-46-9e, pages 23-25 (2008).
    [PDF]
  • Mesure de la déformation d’une surface libre par analyse du déplacement apparent d’un motif aléatoire de points
    M. Rabaud, F. Moisy and J. Rolland, Congrès Français de Mécanique (2007).
    [PDF]


Last modification: April 28 2016, 01:23:05.