Open AccessReal-time visualization of Karman vortex street in water flow field by using digital holography
Author(s) -
Weiwei Sun,
Jianlin Zhao,
Jianglei Di,
Qian Wang,
Le Wang
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.020342
Subject(s) - kármán vortex street , holographic interferometry , holography , optics , vortex , digital holography , flow visualization , physics , flow (mathematics) , field (mathematics) , interferometry , mechanics , mathematics , turbulence , reynolds number , pure mathematics
The Karman vortex street generated behind a circular cylinder in water flow field is displayed and analyzed in real time by means of digital holography. Using a modified Mach-Zehnder interferometer, a digital hologram of the flow field in still state and then a video of continuous digital holograms in flowing state are recorded at 14.6 frames per second by a CCD camera, respectively. A series of sequential phase maps of the flow field are numerically reconstructed from the holograms in different states above based on double-exposure holographic interferometry. By seriating these phase maps, the shape and evolution of Karman vortex street can be displayed in real time in the form of a movie. For comparison, numerical simulation of the Karman vortex street under the boundary conditions adopted in the experiment is also presented, and the consistent results indicate that the experimental observation of Karman vortex street by using digital holography is successful and feasible.