Multi-frame pyramid correlation for time-resolved PIV

A novel technique is introduced to increase the precision and robustness of time-resolved particle image velocimetry (TR-PIV) measurements. The innovative element of the technique is the linear combination of the correlation signal computed at different separation time intervals. The domain of the correlation signal resulting from different temporal separations is matched via homothetic transformation prior to the averaging of the correlation maps. The resulting ensemble-averaged correlation function features a significantly higher signal-to-noise ratio and a more precise velocity estimation due to the evaluation of a larger particle image displacement. The method relies on a local optimization of the observation time between snapshots taking into account the local out-of-plane motion, continuum deformation due to in-plane velocity gradient and acceleration errors. The performance of the pyramid correlation algorithm is assessed on a synthetically generated image sequence reproducing a three-dimensional Batchelor vortex; experiments conducted in air and water flows are used to assess the performance on time-resolved PIV image sequences. The numerical assessment demonstrates the effectiveness of the pyramid correlation technique in reducing both random and bias errors by a factor 3 and one order of magnitude, respectively. The experimental assessment yields a significant increase of signal strength indicating enhanced measurement robustness. Moreover, the amplitude of noisy fluctuations is considerably attenuated and higher precision is obtained for the evaluation of time-resolved velocity and acceleration.

[1]  Joseph Katz,et al.  Instantaneous pressure and material acceleration measurements using a four-exposure PIV system , 2006 .

[2]  A. Prasad,et al.  Optimization procedure for pulse separation in cross-correlation PIV , 1996 .

[3]  Christian Haigermoser,et al.  Application of an acoustic analogy to PIV data from rectangular cavity flows , 2009 .

[4]  Bhimsen K. Shivamoggi,et al.  Axial flow in trailing line vortices , 1979 .

[5]  Fulvio Scarano,et al.  Lagrangian and Eulerian pressure field evaluation of rod-airfoil flow from time-resolved tomographic PIV , 2011 .

[6]  M. Gharib,et al.  On errors of digital particle image velocimetry , 1997 .

[7]  F. Scarano.  Iterative image deformation methods in PIV , 2002 .

[8]  Fulvio Scarano,et al.  Three-dimensional evolution of flow structures in transitional circular and chevron jets , 2011 .

[9]  J. Westerweel,et al.  Single-pixel resolution ensemble correlation for micro-PIV applications , 2004 .

[10]  T. Persoons,et al.  Improving the measurement accuracy of PIV in a synthetic jet flow , 2008 .

[11]  J. Westerweel,et al.  Generalized displacement estimation for averages of non-stationary flows , 2011 .

[12]  Edward H. Adelson,et al.  The Laplacian Pyramid as a Compact Image Code , 1983, IEEE Trans. Commun..

[13]  Richard D. Keane,et al.  Optimization of particle image velocimeters. I, Double pulsed systems , 1990 .

[14]  Cameron V. King,et al.  Assessment of pressure field calculations from particle image velocimetry measurements , 2010 .

[15]  Fulvio Scarano,et al.  Advances in iterative multigrid PIV image processing , 2000 .

[16]  Ronald Adrian,et al.  Optimization of particle image velocimeters , 1990, Other Conferences.

[17]  A. Fincham,et al.  Advanced optimization of correlation imaging velocimetry algorithms , 2000 .

[18]  R. Adrian.  Particle-Imaging Techniques for Experimental Fluid Mechanics , 1991 .

[19]  F. Durst,et al.  Applications of Laser Techniques to Fluid Mechanics , 1991 .

[20]  S. Wereley,et al.  A PIV Algorithm for Estimating Time-Averaged Velocity Fields , 2000 .

[21]  Tommaso Astarita,et al.  Analysis of interpolation schemes for image deformation methods in PIV , 2005 .

[22]  Fulvio Scarano,et al.  Counter-hairpin vortices in the turbulent wake of a sharp trailing edge , 2011, Journal of Fluid Mechanics.

[23]  Richard D. Keane,et al.  Theory of cross-correlation analysis of PIV images , 1992 .

[24]  Ferry Schrijer,et al.  Effect of predictor–corrector filtering on the stability and spatial resolution of iterative PIV interrogation , 2008 .

[25]  Tommaso Astarita,et al.  Analysis of weighting windows for image deformation methods in PIV , 2007 .

[26]  Scott C. Morris,et al.  Shear-Layer Instabilities: Particle Image Velocimetry Measurements and Implications for Acoustics , 2011 .

[27]  Christian J. Kähler,et al.  Wall-shear-stress and near-wall turbulence measurements up to single pixel resolution by means of long-distance micro-PIV , 2006 .

[28]  Michel Stanislas,et al.  Main results of the third international PIV Challenge , 2008 .

[29]  Markus Raffel,et al.  Particle Image Velocimetry: A Practical Guide , 2002 .

[30]  Bias errors in PIV : the pixel locking effect revisited , 2010 .

[31]  A. Prasad.  Particle image velocimetry , 2000 .

[32]  Fulvio Scarano,et al.  An advection-based model to increase the temporal resolution of PIV time series , 2011, Experiments in fluids.

[33]  R. Ventas,et al.  Simultaneous assessment of peak-locking and CCD readout errors through a multiple Δt strategy , 2012 .

[34]  L. Lourenço.  Particle Image Velocimetry , 1989 .

[35]  J. Westerweel.  Fundamentals of digital particle image velocimetry , 1997 .

[36]  Mathieu Legrand,et al.  Multiple Δt strategy for particle image velocimetry (PIV) error correction, applied to a hot propulsive jet , 2009 .

[37]  Christian J. Kähler,et al.  Fundamentals of multiframe particle image velocimetry (PIV) , 2007 .

[38]  F. Scarano,et al.  Time-resolved analysis of circular and chevron jets transition by tomo-PIV , 2010 .

[39]  Giorgio Bonmassar,et al.  Improved cross-correlation for template matching on the Laplacian pyramid , 1998, Pattern Recognit. Lett..

[40]  ADAPTIVE MULTI-FRAME PIV , 2004 .

[41]  Christian J. Kähler,et al.  Comparison of CCD, CMOS and intensified cameras , 2007 .

[42]  A. M. Fincham,et al.  Low cost, high resolution DPIV for measurement of turbulent fluid flow , 1997 .

[43]  Jürgen Kompenhans,et al.  Particle Image Velocimetry - A Practical Guide (2nd Edition) , 2007 .