8th European Postgraduate Fluid Dynamics Conference

6th – 9th July 2016
Warsaw, Poland

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Background Oriented Schlieren in a Density Stratified Fluid

Lilly Verso1, Alex Liberzon1
1School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University
Non-intrusive quantitative fluid density measurements methods are essential in the stratified flow experiments. Inthis study, an important extension of the background oriented Schlieren (BOS) is proposed. The extension enables an accurate reconstruction of the density field in stratified liquid experiments. Typically the experiments areperformed by the light source, background pattern and the camera positioned on the opposite sides of a transparent vessel. The multi-media imaging through air-glass-water-glass-air leads to an additional aberration that destroys the reconstruction. Atwo-step calibration and image remapping transform are the key components that correct the images through the stratified media and provide a non-intrusive full-field density measurements of transparent liquids.The developed procedureis extensively tested in an air/water double layer system and in a 4-layers salty-water configuration composed bysolutions of increased
Keywords: Experimental techniques, Geophysical flows
Figure 1: (Left) Reconstruction of the density field of a four layers saline solution. (Right) density profile (z) of the previous stratified setup. Solide line - correct solution using the new method,dashed line - the Poisson solution without