Abstract
We present measurements of grid turbulence using 2D particle image velocimetry taken immediately downstream from the grid at a Reynolds number of Re M = 16500 where M is the rod spacing. A long field of view of 14M × 4M in the down- and cross-stream directions was achieved by stitching multiple cameras together. Two uniform biplanar grids were selected to have the same M and pressure drop but different rod diameter D and cross-section. A large data set (104 vector fields) was obtained to ensure good convergence of second-order statistics. Estimations of the dissipation rate \(\varepsilon\) of turbulent kinetic energy (TKE) were found to be sensitive to the number of mean-squared velocity gradient terms included and not whether the turbulence was assumed to adhere to isotropy or axisymmetry. The resolution dependency of different turbulence statistics was assessed with a procedure that does not rely on the dissipation scale η. The streamwise evolution of the TKE components and \(\varepsilon\) was found to collapse across grids when the rod diameter was included in the normalisation. We argue that this should be the case between all regular grids when the other relevant dimensionless quantities are matched and the flow has become homogeneous across the stream. Two-point space correlation functions at x/M = 1 show evidence of complex wake interactions which exhibit a strong Reynolds number dependence. However, these changes in initial conditions disappear indicating rapid cross-stream homogenisation. On the other hand, isotropy was, as expected, not found to be established by x/M = 12 for any case studied.
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Abbreviations
- CF:
-
Correlation function
- D :
-
Rod diameter
- M :
-
Spacing between two nearest parallel grid rods
- s x :
-
Sampling variance
- TKE:
-
Turbulent kinetic energy
- \(\left\langle * \right\rangle \) :
-
Time average of *
- \(\varepsilon\) :
-
Average dissipation rate of TKE
- η:
-
Kolmogorov length scale
- λ:
-
Taylor microscale
- ν:
-
Kinematic viscosity
- σ:
-
Grid solidity ratio σ = (D/M)(2 − D/M)
- px:
-
Pixels
- \({\bf U} = \left\langle {\bf U} \right\rangle + {\bf u}\) :
-
Total velocity
- \(\left\langle{\bf U}\right\rangle = U{\bf e}_{x} + V{\bf e}_{y} + W{\bf e}_{z}\) :
-
Mean velocity
- u = u e x + v e y + w e z :
-
Fluctuating velocity
- \(u' = \sqrt{\left\langle u^{2}\right\rangle }\) :
-
Root mean square of u
- \(U_{\infty}\) :
-
Free-stream velocity
- Re M :
-
\(\frac{U_{\infty}M}{\nu}\)
- Re λ :
-
\( \frac{u'\lambda}{\nu}\)
References
Batchelor GK (1948) Energy decay and self-preserving correlation functions in isotropic turbulence. Q Appl Math 6(7):97–116
Batchelor GK (1953) The theory of homogeneous turbulence. Cambridge University Press, Cambridge
Benedict LH, Gould RD (1996) Towards better uncertainty estimates for turbulence statistics. Exp Fluids 22:129–136
Bennett JC, Corrsin S (1978) Small reynolds number nearly isotropic turbulence in a straight duct and a contraction. Phys Fluids 21(12):2129–2140
Buchmann NA, Atkinson C, Soria J (2010) Tomographic and stereoscopic piv measurements of grid-generated homogeneous turbulence. In: Proceedings of the 15th Int Symp on Applications of Laser Techniques to Fluid Mechanics, Lisbon
Carr Z, Ahmed K, Forliti D (2009) Spatially correlated precision error in digital particle image velocimetry measurements of turbulent flows. Exp Fluids 47:95–106
Comte-bellot G, Corrsin S (1966) The use of a contraction to improve the isotropy of grid-generated turbulence. J Fluid Mech Digit Arch 25(4):657–682
Corrsin S (1963) Turbulence: experimental methods. Handbuch der Physik 8(2):524–533
Ertunç O, Özyilmaz N, Lienhart H, Durst F, Beronov K (2010) Homogeneity of turbulence generated by static-grid structures. J Fluid Mech 654:473–500
George WK (1992) The decay of homogeneous isotropic turbulence. Phys Fluids A Fluid Dyn 4(7):1492–1509
George WK, Wang H (2009) The exponential decay of homogeneous turbulence. Phys Fluids 21(2):025108
Huang Z, Olson JA, Kerekes RJ, Green SI (2006) Numerical simulation of the flow around rows of cylinders. Comput Fluids 35(5):485–491
Jayesh, Warhaft Z (1992) Probability distribution, conditional dissipation, and transport of passive temperature fluctuations in grid-generated turbulence. Phys Fluids A Fluid Dyn 4(10):2292–2307
Keane RD, Adrian RJ (1990) Optimization of particle image velocimeters. Part I: double pulsed systems. Meas Sci Tech 1:1202–1215
Krogstad P, Davidson PA (2010) Is grid turbulence saffman turbulence? J Fluid Mech 642:373–394
Krogstad P, Davidson PA (2011) Freely decaying, homogeneous turbulence generated by multi-scale grids. J Fluid Mech 680:417–434
Kumar RS, Sharma A, Agrawal A (2008) Simulation of flow around a row of square cylinders. J Fluid Mech 606:369–397
Laizet S, Lamballais E, Vassilicos J (2010) A numerical strategy to combine high-order schemes. Comput Fluids 39(3):471–484
Lavoie P, Avallone G, De Gregorio F, Romano G, Antonia R (2007) Spatial resolution of piv for the measurement of turbulence. Exp Fluids 43:39–51
Lavoie P, Djenidi L, Antonia RA (2007) Effects of initial conditions in decaying turbulence generated by passive grids. J Fluid Mech 585(1):395–420
Mi J, Antonia R (2010) Approach to local axisymmetry in a turbulent cylinder wake. Exp Fluids 48:933–947
Nagata K, Suzuki H, Sakai Y, Hayase T, Kubo T (2008) Direct numerical simulation of turbulent mixing in grid-generated turbulence. Phys Scripta T132:014,054
Nicolaides D, Honnery D, Soria J (1998) Measurements of velocity and vorticity in grid turbulence using PIV. Monash University, Melbourne
Poelma C, Westerweel J, Ooms G (2006) Turbulence statistics from optical whole-field measurements in particle-laden turbulence. Exp Fluids 40:347–363
Raffel M, Willert CE, Wereley ST, Kompenhans J (2007) Particle image velocimetry, 2nd edn. Springer, Berlin
Roach PE (1987) The generation of nearly isotropic turbulence by means of grids. Int J Heat Fluid Flow 8(2):82–92
Saarenrinne P, Piirto M (2000) Turbulent kinetic energy dissipation rate estimation from piv velocity vector fields. Exp Fluids 29:S300–S307
Saffman PG (1967) The large-scale structure of homogeneous turbulence. J Fluid Mech 27(03):581–593
Seoud RE, Vassilicos JC (2007) Dissipation and decay of fractal-generated turbulence. Phys Fluids 19(10):105108
Tanaka T, Eaton J (2007) A correction method for measuring turbulence kinetic energy dissipation rate by piv. Exp Fluids 42:893–902
Taylor GI (1935) Statistical theory of turbulence. Proc R Soc Lond Ser A Math Phys Sci 151(873):421–444
Tomkins CD, Adrian RJ (2003) Spanwise structure and scale growth in turbulent boundary layers. J Fluid Mech 490:37–74
Uberoi MS, Wallis S (1967) Effect of grid geometry on turbulence decay. Phys Fluids 10(6):1216–1224
Ullum U, Schmidt JJ, Larsen PS, McCluskey DR (1998) Statistical analysis and accuracy of piv data. J Vis 1(2):205–216
von Karman T, Howarth L (1938) On the statistical theory of isotropic turbulence. Proc R Soc Lond Ser A Math Phys Sci 164(917):192–215
Westerweel J, Dabiri D, Gharib M (1997) The effect of a discrete window offset on the accuracy of cross-correlation analysis of digital piv recordings. Exp Fluids 3(23):20–28
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Cardesa, J.I., Nickels, T.B. & Dawson, J.R. 2D PIV measurements in the near field of grid turbulence using stitched fields from multiple cameras. Exp Fluids 52, 1611–1627 (2012). https://doi.org/10.1007/s00348-012-1278-4
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DOI: https://doi.org/10.1007/s00348-012-1278-4