Use of the reflective background oriented schlieren technique to measure free surface deformations in a thin liquid layer non-uniformly heated from below

Kochkin, Dmitry; Mungalov, A S; Зайцев, Д. В.; Kabov, Oleg

doi:10.1016/j.expthermflusci.2021.110576

Cited by 6 publications

(2 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moon glade background oriented schlieren (MGBOS) is a reflective variant of BOS, a synthetic schlieren technique (Vinnichenko et al 2020;Kochkin et al 2022;Srivastava et al 2022). BOS, in transmission mode, is employed for systems that have reasonable optical access through the bulk and is used to quantify the physical quantities by determining the displacement attached to a white light source and the reflection of the pattern from the free surface of the liquid is captured using a camera and lens system.…”

Section: Data Reduction Methodologymentioning

confidence: 99%

On the interfacial deformations and thermal characteristics exhibiting self-similar behavior under the action of a line heat source

2023

View full text Add to dashboard Cite

Interfacial dynamics resulting from a heating source located near the interface play a crucial role in dictating the heat and momentum transport in the near-interface region. This paper aims toward simultaneous characterization of interfacial deformation and thermal behavior under the action of a line heating source placed below the interface. Experiments have been conducted on aqueous glycerol with a heating wire at different power inputs and depths from the interface. The interfacial deformations are mapped and quantified by employing moon-glade background oriented schlieren, which offers real-time, non-intrusive whole field measurements based on the deflection of light rays from liquid interface. Infrared thermography is used to measure transient interfacial temperature variations. Results show that the interface exhibits a convex-shaped deformation under the influence of the heating wire for all cases of heating power and depth. The maximum interface temperature coincides with the peak interfacial deformation. However, the region of thermal influence is smaller compared to the deformed region. Non-dimensionalization of transient interface deformation and temperature profiles establishes the underlying similarity of the phenomenon as non-dimensional interface perturbation profiles overlap for all cases of height and heating power. These characteristics are also observed for normalized temperature profiles at different wire depths.

show abstract

Section: Data Reduction Methodologymentioning

confidence: 99%

On the interfacial deformations and thermal characteristics exhibiting self-similar behavior under the action of a line heat source

2023

View full text Add to dashboard Cite

show abstract

“…To the authors' knowledge, this is the first study to compare the performance of multiple optical techniques for surface reconstruction. The TIR-D and M-G techniques, due to their recency, are featured in limited studies other than the original work (Jain et al, 2022;Jain, Gauthier, Lohse, et al, 2021;Jain, Vega-Martínez, et al, 2021;Kochkin et al, 2022;Mungalov & Derevyannikov, 2021;Rudenko et al, 2022). These techniques have also gone unnoticed in reviews of optical techniques for surface measurements such as a recent comprehensive review by Gomit et al (2022).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Schlieren-based techniques for measurements of a turbulent and wavy free surface

Bheeroo

Mandel

2023

Preprint

View full text Add to dashboard Cite

The free surface at an air-water interface can provide information regarding bathymetric complexities, as well as the subsurface flow. We present a comparison of the performance of two recent advances in light-based optical techniques for free surface measurements, Total Internal Reflection-Deflectometry and Moon-Glade Background Oriented Schlieren, with the more established method of Free-Surface Synthetic Schlieren. We make use of an optical flow algorithm over the more traditional Digital Image Correlation, in order to obtain higher spatial resolution data across the imaged free surface domain. The Optical flow algorithm presents additional benefits, such as computational efficiency and robustness in capturing large displacements and straining of tracked features. The three optical techniques are assembled in synchronization to image two free surface conditions: (1) a free surface being impinged upon by an underlying turbulent, free-shear flow and (2) a random and irregular wave field induced by a free jet. Using the high-resolution measurements, we provide insight on the emergence of multiple free surface dynamics for a turbulent free surface and dissect the local hydrodynamics of the free surface for several wave forcings. We present a comprehensive discussion on the benefits and drawbacks of each technique, including suggestions on the suitability of each technique for several experimental constraints.

show abstract

Comparison of schlieren-based techniques for measurements of a turbulent and wavy free surface

Bheeroo

Mandel

2023

Exp Fluids

View full text Add to dashboard Cite

The free surface at an air–water interface can provide information regarding bathymetric complexities, as well as the subsurface flow. We present a comparison of the performance of two recent advances in light-based optical techniques for free surface measurements, total internal reflection-deflectometry and moon-glade background-oriented schlieren, with the more established method of free surface synthetic schlieren. We make use of an optical flow algorithm over the more traditional digital image correlation, in order to obtain higher spatial resolution data across the imaged free surface domain. The optical flow algorithm presents additional benefits, such as computational efficiency and robustness in capturing large displacements and straining of tracked features. The three optical techniques are assembled in synchronization to image two free surface conditions: (1) a free surface being impinged upon by an underlying turbulent, free-shear flow and (2) a random and irregular wave field induced by a free jet. Using the high-resolution measurements, we provide insight on the emergence of multiple free surface dynamics for a turbulent free surface. We present a comprehensive discussion on the benefits and drawbacks of each technique, including suggestions on the suitability of each technique for several experimental constraints. Graphical abstract

show abstract

Use of the reflective background oriented schlieren technique to measure free surface deformations in a thin liquid layer non-uniformly heated from below

Cited by 6 publications

References 9 publications

On the interfacial deformations and thermal characteristics exhibiting self-similar behavior under the action of a line heat source

On the interfacial deformations and thermal characteristics exhibiting self-similar behavior under the action of a line heat source

Comparison of Schlieren-based techniques for measurements of a turbulent and wavy free surface

Comparison of schlieren-based techniques for measurements of a turbulent and wavy free surface

Contact Info

Product

Resources

About