An adaptive sampling algorithm for Doppler-shift fluorescence velocimetry in high-speed flows. (March 2017)

• Record Type: Journal Article
• Authors: Le Page, Laurent M.; O'Byrne, Sean
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 190(2017)
• Page Start: 69
• Page End: 77
• Publication Date: 2017-03
• Subjects: Adaptive sampling -- PLIF -- Bayesian updating -- Lineshape fitting; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2017.01.022
• Languages: English
• ISSNs: 0022-4073

Abstract

Abstract: We present an approach to improving the efficiency of obtaining samples over a given domain for the peak location of Gaussian line-shapes. The method uses parameter estimates obtained from previous measurements to determine subsequent sampling locations. The method may be applied to determine the location of a spectral peak, where the monetary or time cost is too high to allow a less efficient search method, such as sampling at uniformly distributed domain locations, to be used. We demonstrate the algorithm using linear least-squares fitting of log-scaled planar laser-induced fluorescence data combined with Monte-Carlo simulation of measurements, to accurately determine the Doppler-shifted fluorescence peak frequency for each pixel of a fluorescence image. A simulated comparison between this approach and a uniformly spaced sampling approach is carried out using fits both for a single pixel and for a collection of pixels representing the fluorescence images that would be obtained in a hypersonic flow facility. In all cases, the peak location of Doppler-shifted line-shapes were determined to a similar precision with fewer samples than could be achieved using the more typical uniformly distributed sampling approach. Abstract : Highlights: A new method to choose samples to locate the peak of a Gaussian based on previous measurements. Reduces the number of samples needed for spectroscopic measurement of velocity. Peak locations were acquired with fewer samples compared with equi-spaced sampling.