Improved Fringe Carrier Technique For Unambiguous Determination Of Holographically Recorded Displacements

Plotkowski, Paul D.; Hung, Y. Y.; Hovanesian, J. D.; Gerhart, Grant R.

doi:10.1117/12.7973571

Cited by 26 publications

(5 citation statements)

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“…whether the surface has moved toward or away from the observer, 1-2 and in assigning the correct fringe orders. In overcoming these difficulties, the carrier fringe technique [1][2][3][4][5][6] is frequently used. The basic principle of the technique is to introduce a known set of linear carrier fringes which modulates the conventional deformation fringes.…”

Section: The Use Of Carrier Fringes and Fft In Holographic Nondestrucmentioning

confidence: 99%

The Use of Carrier Fringes and FFT in Holographic Nondestructive Testing

Quan

Tay

Shang

2001

Experimental Techniques

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Section: The Use Of Carrier Fringes and Fft In Holographic Nondestrucmentioning

confidence: 99%

The Use of Carrier Fringes and FFT in Holographic Nondestructive Testing

Quan

Tay

Shang

2001

Experimental Techniques

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“…The interferogram I t (figure 3a) is decomposed into its phase ψ t and magnitude M t (figure 3b) with a Fourier transform technique (Plotkowski, Hung & Gerhart 1985;Matthys et al 1988;Kreis 2005). Since all interferograms resulting from experiments are subject to some noise which distorts the analysis process, a bandpass filter is used to remove low frequency background intensity variation of the laser beam and high frequency noise, a procedure made possible by the present use of the finite-fringe mode (appendix A).…”

Section: Data Processingmentioning

confidence: 99%

Leidenfrost drops cooling surfaces: theory and interferometric measurement

et al. 2017

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When a liquid drop is placed on a highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon is referred to as the Leidenfrost effect. The thermally insulating vapour film results in a severe reduction of the heat transfer rate compared to experiments at lower surface temperatures, where the drop is in direct contact with the solid surface. A commonly made assumption is that this solid surface is isothermal, which is at least questionable for materials of low thermal conductivity, resulting in an overestimation of the surface temperature and heat transfer for such systems. Here we aim to obtain more quantitative insight into how surface cooling affects the Leidenfrost effect. We develop a technique based on Mach-Zehnder interferometry to investigate the surface cooling of a quartz plate by a Leidenfrost drop. The three-dimensional plate temperature field is reconstructed from interferometric data by an Abel inversion method using a basis function expansion of the underlying temperature field. By this method we are able to quantitatively measure the local cooling inside the plate, which can be as strong as 80 K. We develop a numerical model which shows good agreement with experiments and enables extending the analysis beyond the experimental parameter space. Based on the numerical and experimental results we quantify the effect of surface cooling on the Leidenfrost phenomenon. By focusing on the role of the solid surface we provide new insights into the Leidenfrost effect and demonstrate how to adjust current models to account for non-isothermal solids and use previously obtained isothermal scaling laws for the neck thickness and evaporation rate.

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“…analysis method is not effective in retrieving phases from close-loop fringes. Plotkowski et al[5] described a carrier fringe technique for unambiguous determination of displacement directions as well as producing open-loop fringes for analysis. Carrier fringes are generated by displacing the object beam source by a distance of D O by rotating the object beam mirror.…”

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confidence: 99%