Author: Ofuchi César Yutaka Coutinho Fabio Rizental Neves Flávio de Arruda Lucia Valéria Ramos Morales Rigoberto Eleazar Melgarejo
Publisher: MDPI
E-ISSN: 1424-8220|16|8|1250-1250
ISSN: 1424-8220
Source: Sensors, Vol.16, Iss.8, 2016-08, pp. : 1250-1250
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Abstract
In this paper the extended autocorrelation velocity estimator is evaluated and compared using a nondestructive ultrasonic device. For this purpose, three velocity estimators are evaluated and compared. The autocorrelation method (ACM) is the most used and well established in current ultrasonic velocity profiler technology, however, the technique suffers with phase aliasing (also known as the Nyquist limit) at higher velocities. The cross-correlation method (CCM) is also well known and does not suffer with phase aliasing as it relies on time shift measurements between emissions. The problem of this method is the large computational burden due to several required mathematical operations. Recently, an extended autocorrelation method (EAM) which combines both ACM and CCM was developed. The technique is not well known within the fluid engineering community, but it can measure velocities beyond the Nyquist limit without the ACM phase aliasing issues and with a lower computational cost than CCM. In this work, all three velocity estimation methods are used to measure a uniform flow of the liquid inside a controlled rotating cylinder. The root-mean-square deviation variation coefficient (
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