Abstract
A compact active grid is developed with which a pipe flow can be stirred in order to enhance the turbulence. The active grid is composed of a stationary and a rotating disk with characteristic hole patterns. This active grid is placed inside the pipe, allowing flow to pass through it. With only one moving part, the design is much less complicated than current active grids. Several combinations of perforated disks are investigated, and the resulting control over the turbulent intensity and spectral energy distribution is quantified over a wide range of rotation frequencies. We find that significant turbulent fluctuations are introduced mainly in the energy-containing range and partially also in the inertial subrange. These additional fluctuations represent up to 25 % of the total energy and are not caused by pulsations of the mean flow. The compact active grid will be of use where efficient mixing in limited space is required and in applications when the introduction of specific lengthscales is desirable, such as in premixed burners.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Antonia RA (2003) On estimating mean and instantaneous turbulent energy dissipation rates with hot wires. Exp Therm Fluid Sci 27(2):151–157, doi:10.1016/s0894-1777(02)00259-5, 6th international thermal anemometry symposium
Bird RB, Stewart WE, Lightfoot EN (2002) Transport phenomena. 2nd edn. Wiley, New York, NY
Bruun H (1995) Hot Wire Anemometry. Oxford University Press, Oxford
Burattini P (2008) The effect of the X-wire probe resolution in measurements of isotropic turbulence. Meas Sci Technol 19(11):115,405. doi:10.1088/0957-0233/19/11/115405
Cadot O, Titon JH, Bonn D (2003) Experimental observation of resonances in modulated turbulence. J Fluid Mech 485:161–170. doi:10.1017/S0022112003004592
Cekli HE, Tipton C, van de Water W (2010) Resonant enhancement of turbulent energy dissipation. Phys Rev Lett 105:044,503. doi:10.1103/PhysRevLett.105.044503
Chiekh MB, Béra JC, Sunyach M (2012) Synthetic jet control for flows in a diffuser: vectoring, spreading and mixing enhancement. J Turbul 4(32):1–12. doi:10.1088/1468-5248/4/1/032
Coffey CJ, Hunt GR, Seoud RE, Vassilicos JC (2007) Mixing effectiveness of fractal grids for inline static mixers. Proof of concept report for the attention of imperial innovations. Imperial College London
Dahm WJA, Southerland KB (1997) Experimental assessment of taylor’s hypothesis and its applicability to dissipation estimates in turbulent flows. Phys Fluids 9(7):2101–2107. doi:10.1063/1.869329
Driscoll JF (2008) Turbulent premixed combustion: flamelet structure and its effect on turbulent burning velocities. Prog Energy Combust Sci 34(1):91–134. doi:10.1016/j.pecs.2007.04.002
Gad-el Hak M, Corrsin S (1974) Measurements of the nearly isotropic turbulence behind a uniform jet grid. J Fluid Mech 62(1):115–143
Hultmark M, Smits AJ (2010) Temperature corrections for constant temperature and constant current hot-wire anemometers. Meas Sci Technol 21(10):105,404. doi:10.1088/0957-0233/21/10/105404
Kang HS, Chester S, Meneveau C (2003) Decaying turbulence in an active-grid-generated flow and comparisons with large-eddy simulation. J Fluid Mech 480:129–160. doi:10.1017/S0022112002003579
Kuczaj AK, Geurts BJ (2006) Mixing in manipulated turbulence. J Turbul 7(67):1–28. doi:10.1080/14685240600827534
Kuczaj AK, Geurts BJ, Lohse D (2006) Response maxima in time-modulated turbulence: direct numerical simulations. Europhys Lett 73(6):851–857. doi:10.1209/epl/i2005-10486-2
Kuczaj AK, Geurts BJ, Lohse D, van de Water W (2008) Turbulence modification by periodically modulated scale-dependent forcing. Comput Fluids 37(7):816–824. doi:10.1016/j.compfluid.2007.01.012
Larssen JV, Devenport WJ (2011) On the generation of large-scale homogeneous turbulence. Exp Fluids 50(5):1207–1223. doi:10.1007/s00348-010-0974-1
Lee T, Budwig R (1991) Two improved methods for low-speed hot-wire calibration. Meas Sci Technol 2(7):643. doi:10.1088/0957-0233/2/7/011
Ling SC, Wan CA (1972) Decay of isotropic turbulence generated by a mechanically agitated grid. Phys Fluids 15(8):1363. doi:10.1063/1.1694093
Lohse D (2000) Periodically kicked turbulence. Phys Rev E 64(4):4946–4949. doi:10.1103/PhysRevE.62.4946
Makita H (1991) Realization of a large scale turbulence field in a small wind tunnel. Fluid Dyn Res 8(1-4):53–64. doi:10.1016/0169-5983(91)90030-M
Mydlarski L, Warhaft Z (1996) On the onset of high-reynolds-number grid-generated wind tunnel turbulence. J Fluid Mech 320:331–368. doi:10.1017/S0022112096007562
O’Neill PL, Nicolaides D, Honnery D, Soria J (2004) Autocorrelation functions and the determination of integral length with reference to experimental and numerical data. In: 15th Australasian fluid mechanics conference. The University of Sydney
Peters N (2004) Turbulent combustion. Cambridge University Press, Cambridge
Poorte REG, Biesheuvel A (2002) Experiments on the motion of gas bubbles in turbulence generated by an active grid. J Fluid Mech 461:127–154
Pope SB (2006) Turbulent flows. Cambridge University Press, Cambridge
Welch P (1967) The use of fast fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms. Audio Electroacoust IEEE Trans 15(2):70–73. doi:10.1109/tau.1967.1161901
Acknowledgments
This project is sponsored by Technology Foundation STW, The Netherlands, Project Number 10425.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Verbeek, A.A., Pos, R.C., Stoffels, G.G.M. et al. A compact active grid for stirring pipe flow. Exp Fluids 54, 1594 (2013). https://doi.org/10.1007/s00348-013-1594-3
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00348-013-1594-3