# Interferometric Study of the Heat Transfer Phenomena Induced by Rapid Heating of Nickel Sheet
## 1 Introduction
They also checked the forced convection characteristics in a meso-scale channel with inconstant cross-sections using finite difference solution and validated these results with the experimental results from Mach-Zehnder interferometry [19]. [PERSON] and [PERSON] [20] performed experimental studies to measure the heat transfer phenomena under thermo-diffusion experiments, using Mach-Zehnder interferometry at reduced gravity. They explained the deviations reflected in the measured results between the temperature differences at the hot and cold sides of a cell using optical techniques and Peltier elements. [PERSON] et al. [21] confirmed the availability of the bumped channel for the micro heat sink which is to measure the density distributions of supersonic flow in the microchannel using a phase-shifting interferometer. The results were validated by the results from a numerical study of basic density field and heat transfer simulations. [PERSON], et al. [22] performed an experimental study to determine the temperature field and Nusselt number for a methane/air slot flame impinging into a cylindrical surface. In order to determine the temperature, Mach-Zehnder interferometry was used. The effects of the operating conditions, Reynolds number, equivalence ratio, distance between the burner and impingement surface, and the surface diameter were considered in order to analyze the thermal fluid flow phenomena. Additionally, there were a few experimental studies focused on obtaining results for the thermo-acoustic wave phenomena using interferometric apparatuses. [PERSON] et al. [23] measured the flow characteristics from a stack of parallel plates at relatively low drive ratios between 1.0% and 1.5% using PIV, and they validated these results using the results of numerical analysis. [PERSON] et al. [24] investigated the flow phenomena in the stack of a thermo-acoustic refrigerator using the PIV method. They found that vortex flow fields are generated during the half period of the acoustic cycle when the working fluid flows out of the stack, and they showed the flow phenomena using eight vortices according to eight different phases within an acoustic cycle. [PERSON] et al. [25] performed various experimental studies using PIV to find the vortex generation processes under higher drive ratios (by 2%), using two stacks with 1 and 5-mm thick plates, with fixed spacing between the plates of 5 and 10 mm, respectively. They utilized nine figures of vortices out of 20 phases to describe an acoustic cycle, and they found that the most significant vortex structures turned up in the ejection stage (when the fluid flows out of the stack). [PERSON] et al. (2020) judged that the ratio between Strouhal and Reynolds numbers is an important factor in deciding the vortex shapes behind the stack plates, and they also investigated the porous effects and the end shape of the plate. [PERSON] et al. (2019); [PERSON] et al. (2019); [PERSON] et al. (2020); [PERSON] et al. (2020) found that the various parameters and Reynolds numbers were around 5000. They also tried to prove the relationship between the Reynolds number and the Strouhal number according to the vortex shedding frequency and the evolution of the vortex wake patterns. The fluctuating fields were classified as the ejection stage and the suction stage. The two-dimensional temperature fields were also observed via planar laser-induced fluorescence and combined with the velocity fields. The intensive studies on the thermo-acoustic phenomena created by thermal effects were being investigated numerically and experimentally at the end of the twentieth century. However, there were a lot of problems, like various errors of numerical schemes, inaccuracy of the experimental methodologies, and the difficulty of visualization in thermal flow fields with various parameters. In the present study, the heat transfer phenomena induced by the rapid heating of a metal sheet in air are experimentally studied.