A New Application of the Digital Synthetic Schlieren in Lab Experiments of the Internal Waves
Volume 7, Issue 6, December 2018, Pages: 283-288
Received: Dec. 9, 2018;
Published: Dec. 11, 2018
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Qingjun Meng, College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
Yanzhen Gu, College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
Peiliang Li, Ocean College, ZheJiang University, Zhoushan, China
Xinzhu Wu, School of Hydraulic Engineering, Dalian University of Technology, Dalian, China
Laboratory experiment is an important method in the study of ocean internal waves, and the schlieren technique is an effective way to observe the internal waves in the laboratory. The digital synthetic schlieren technique is mostly applied to two-dimensional density-stratified flows. The technique is improved by setting up the Charge Coupled Device (CCD) vertically to shoot the reference images in this research. Then the three-dimensional density-stratified flows can be detected in this way. The authors attempt a set of lab experiments to verify the rationality of this technique. There is a horizontally moving spherule with constant velocity at the interface of the two-layer stratified water in the experiment. The moving spherule generates internal waves between the two-layer fluids. The authors successfully capture the three-dimensional structure of the internal waves generated by the horizontally moving spherule. It is obvious that the internal waves have characteristics of the Kelvin Internal Wake and the quantitative parameters agree well with the previous studies. The experimental results reveal that the improved digital schlieren technique is rational and feasible in the lab internal waves observations. The detailed three-dimensional structure of the internal waves, the internal wave energy distribution and propagation in the whole field and the nonlinear interactions between the internal waves can be further studied through this method in the future.
A New Application of the Digital Synthetic Schlieren in Lab Experiments of the Internal Waves, Earth Sciences.
Vol. 7, No. 6,
2018, pp. 283-288.
W. H. Munk, C. Wunsch, “Abyssal recipes II: energetics of tidal and wind mixing,” Deep-Sea Res. I, 1998, vol. 45, pp. 1977- 2010.
C. Wunsch and R. Ferrari, “Vertical mixing, energy, and the general circulation of the oceans,” Annual Review of Fluid Mechanics, 2004, vol. 36, pp. 281–314.
J. Wei, “Maximum Offset for the Emergency Disengagement and Control of the Deep water Semi-Submersible Platform in Internal Wave,” Ocean Engineering Equipment & Technology, 2017, vol. 4, pp. 29-36.
P. J. Diamessis, S. Wunsch, I. Delwiche, and M. P. Richter, “Nonlinear generation of harmonics through the interaction of an internal wave beam with a model oceanic pycnocline,” Dynamics of Atmospheres and Oceans, 2014, vol. 66, pp. 110–137.
Y. Sugiyama, Y. Niwa, T. Hibiya, “Numerically reproduced internal wave spectra in the deep ocean,” Geophysical Research Letters, 2009, vol. 36, pp. 251-254.
H. Sun, Q. Wang, “Microstructure observations in the upper layer of the South China Sea,” Journal of Oceanography, 2016, vol. 72, pp. 1-10.
J. Yang, J. Wang, R. Lin, “The first quantitative remote sensing of ocean internal waves by Chinese GF-3 SAR satellite,” Acta Oceanologica Sinica, 2017, vol. 36, pp. 118-118.
J. K. Wang, M. Zhang, Z. H. Cai, et al, “SAR imaging simulation of ship-generated internal wave wake in stratified ocean,” Journal of Electromagnetic Waves & Applications, 2017, vol. 31, pp. 1-14.
Ø. A. Arntsen, “Disturbances, lift and drag forces due to the translation of a horizontal circular cylinder in stratified water,” Experiments in fluids, 1996, vol. 21, pp. 387-400.
Z. Xu, Q. Li, V. A. Gorodtsov, “Wave drag of rapidly and horizontally moving Rankine ovoid in uniformly stratified fluid,” Progress in Natural Science, 2008, vol. 18, pp. 723-727.
J. Wang, X. Chen, W. Wang, et al, “Laboratory experiments on the resonance of internal waves on a finite height subcritical topography,” Ocean Dynamics, 2015, vol. 65, pp. 1269-1274.
Y. Dossmann, B. Bourget, C. Brouzet, et al, “Mixing by internal waves quantified using combined PIV/PLIF technique,” Experiments in Fluids, 2016, vol. 57, pp. 132.
G. S. Settles, M. Hargather, “A review of recent developments in schlieren and shadowgraph techniques,” Measurement Science & Technology, 2017, vol. 28.
J. M. Toole, R. W. Schmitt, “Polzin, K. L. Estimates of diapycnal mixing in the abyssal ocean,” Science, 1994, vol. 264, pp. 1120-1123.
S. B. Dalziel, G. O. Hughes, B. R. Sutherland, “Whole-field density measurements by ‘synthetic schlieren’,” Experiments in Fluids, 2000, vol. 28, pp. 322-335.
B. R. Sutherland, S. B. Dalziel, G. O. Hughes, P. F. Linden, “Visualization and measurement of internal waves by ‘synthetic schlieren’. Part 1. Vertically oscillating cylinder,” Journal of Fluid Mechanics, 1999, vol. 390, pp. 93-126.
J. M. Chomaz, P. Bonneton, E. J. Hopfinger, “The structure of the near wake of a sphere moving horizontally in a stratified fluid,” Journal of Fluid Mechanics, 1993, vol. 254, pp. 1-21.