The effect of a discrete window offset on the accuracy of cross-correlation analysis of digital PIV recordings

Westerweel, J.; Dabiri, Dana; Gharib, Morteza

doi:10.1007/s003480050082

Cited by 430 publications

(195 citation statements)

References 7 publications

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“…The laser sheet was estimated by projection onto a millimetric scale and appeared to be approximately 1 mm thick, a dimension comparable to our final interrogation window size. Data were processed using a multi-pass algorithm, (Westerweel et al 1997) with the interrogation window sizes tailored to the local flow regime. This approach was chosen to deal with the large dynamic range of the flow.…”

Section: Piv Setupmentioning

confidence: 99%

High speed PIV applied to aerodynamic noise investigation

et al. 2010

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In this paper, we study the acoustic emissions of the flow over a rectangular cavity. Especially, we investigate the possibility of estimating the acoustic emission by analysis of PIV data. Such a possibility is appealing, since it would allow to directly relate the flow behavior to the aerodynamic noise production. This will help considerably in understanding the noise production mechanisms and to investigate the possible ways of reducing it. In this study, we consider an open cavity with an aspect ratio between its length and depth of 2 at a Reynolds number of 2.4 9 10 4 and 3.0 9 10 4 based on the cavity length. The study is carried out combining high speed two-dimensional PIV, wall pressure measurements and sound measurements. The pressure field is computed from the PIV data. Curle's analogy is applied to obtain the acoustic pressure field. The pressure measurements on the wall of the cavity and the sound measurements are then used to validate the results obtained from PIV and check the range of validity of this approach. This study demonstrated that the technique is able to quantify the acoustic emissions from the cavity and is promising especially for capturing the tonal components on the sound emission.

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Section: Piv Setupmentioning

confidence: 99%

High speed PIV applied to aerodynamic noise investigation

et al. 2010

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“…The computer power currently available at affordable costs allows researchers to perform multiple interrogation steps for a single recording within the minute. The most important advantages of multi-grid techniques are the increase of dynamic range eliminating the constraint of the rule for the in-plane motion (Keane and Adrian 1993) and an increased measurement precision (Soria 1996;Westerweel et al 1997;Scarano and Riethmuller 1999). The introduction of the iterative sub-pixel window shift technique (Lecordier 1997) showed that an important improvement could be obtained also in terms of measurement sub pixel precision.…”

Section: Introductionmentioning

confidence: 99%

Effect of predictor–corrector filtering on the stability and spatial resolution of iterative PIV interrogation

2008

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The stability and resolution of iterative PIV image analysis methods is investigated. The study focuses on the effects of stabilization by means of spatial filtering when implemented into the iterative process. Two filtering approaches are studied: predictor and corrector filtering respectively. A family of convolution filters is proposed, which allows to vary the filtering strength in a systematic way and primarily affects the system stability and to a smaller extent its spatial response. A critical value for the filter parameter is identified which guarantees the stability of the iterative process. A theoretical analysis is provided that determines the asymptotic properties of the iterative method with varying filter parameters. The study is completed with a numerical assessment and concludes with an application to real experiments, showing the consequence of an incorrect implementation of the iterative scheme under experimental conditions.

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“…Most often these are iterative methods based on relative displacement of interrogation areas, both on integer and subpixel displacement [1], [2], [3], [4], [5]. Another group of methods are algorithms based on relative deformation of particular areas with the aim of obtaining suitable deformation function that describes a spatial displacement of particles [5], [7], [8], [9].…”

Section: Modified Image Deformation Methods -Idmmentioning

confidence: 99%

“…It can be concluded that, based on the results of the synthetic tests [1], [2], [8], the foregoing algorithm has a potential to provide greater measurement accuracy of the PIV method compared to the classical approach and it does not substantially increase the time required for the displacement calculation. The main advantage of the algorithm is the especially significant insensitivity to the velocity gradient magnitude inside IO.…”

Section: Modified Image Deformation Methods -Idmmentioning

confidence: 99%

The Verification of Hybrid Image Deformation algorithm for PIV

Novotný¹,

Nováková²

2016

Journal of Middle European Construction and Design of Cars

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The aim of this paper was to test a newly designed algorithm for more accurate calculation of the image displacement of seeding particles when taking measurement using the Particle Image Velocimetry method. The proposed algorithm is based on modification of a classical iterative approach using a three-point subpixel interpolation and method using relative deformation of individual areas for accurate detection of signal peak position. The first part briefly describes the tested algorithm together with the results of the performed synthetic tests. The other part describes the measurement setup and the overall layout of the experiment. Subsequently, a comparison of results of the classical iterative scheme and our designed algorithm is carried out. The conclusion discusses the benefits of the tested algorithm, its advantages and disadvantages. KEYWORDS: PIV, DEFORMATION, ACURACCY, TESTING, HYBRID, ALGORITHM, MEASUREMENT SHRNUTÍCílem této práce bylo otestovat nově navržený algoritmus pro přesnější výpočet posunutí obrazů značkovacích částic při měření metodou Particle Image Velocimetry. Navržený algoritmus je založen na modifikaci klasického iteračního přístupu s využitím tříbodové sub pixelové interpolace a metodě využívající vzájemné deformace jednotlivých oblastí pro přesné stanovení polohy signálového peaku. V první části je stručně popsán testovaný algoritmus spolu s výsledky již provedených syntetických testů. V další části práce je popsána měřicí trať a celkové uspořádání experimentu. Následně je provedeno srovnání výsledků klasického iteračního schématu a námi navrženého algoritmu. V závěru jsou pak diskutovány přínosy testovaného algoritmu jeho výhody a nevýhody.

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The effect of a discrete window offset on the accuracy of cross-correlation analysis of digital PIV recordings

Cited by 430 publications

References 7 publications

High speed PIV applied to aerodynamic noise investigation

High speed PIV applied to aerodynamic noise investigation

Effect of predictor–corrector filtering on the stability and spatial resolution of iterative PIV interrogation

The Verification of Hybrid Image Deformation algorithm for PIV

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