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

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.