Abstract
The purpose of this paper is to show that the measurement of turbulent spectrum using wholefield velocity techniques such as particle image velocimetry (PIV) is possible. Toward this end, data from the axial plane of a self-similar turbulent axisymmetric jet, at a Reynolds number, based on Taylor microscale of 30 has been analyzed. The two-dimensional velocity data are first high-pass filtered, which educes the vortices. An automated method is then used to identify the vortices and measure their properties. By directly measuring the energy of the vortices, it is possible to plot the turbulence spectrum. The spectrum presented here shows the presence of energy containing and inertial regimes. However, the smallest scales have not been resolved in the measurements. The slope of the spectrum in the inertial subrange is about −1.6. The number of vortices in the two regimes have also been measured. The number of vortices in the energy containing regime is substantially smaller than those in the inertial subrange. The technique has been verified by analyzing another dataset. These results show that the direct measurement of vortex properties with reasonable confidence is possible using PIV and an appropriate vortex eduction technique.
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References
Adrian RJ, Christensen KT, Liu Z-C (2000) Analysis and interpretation of instantaneous turbulent velocity fields. Exp Fluids 29:275–290
Agrawal A, Prasad AK, (2002a) Properties of vortices in the self-similar turbulent jet. Exp Fluids 33:565–577
Agrawal A, Prasad AK (2002b) Organizational modes of large-scale vortices in an axisymmetric turbulent jet. Flow Turbul Combust 68:359–377
Agrawal A, Prasad AK (2003) Measurements within vortex cores in a turbulent jet. J Fluids Eng 125:561–568
Boersma BJ, Brethouwer G, Nieuwstadt FTM (1998) A numerical investigation on the effect of the inflow conditions on the self-similar region of a round jet. Phys Fluids 10:899–909
Burattini P, Djenidi L (2004) Velocity and passive scalar characteristics in a round jet with grids at the nozzle exit. Flow Turbul Combust 72:199–218
Hussein H, Capp S, George WK (1994) Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jet. J Fluid Mech 258:31–75
Panchapakesan N, Lumley JL (1993) Turbulence measurements in an axisymmetric jets of air and helium, Part 1. Air jet. J Fluid Mech 246:197–223
Tennekes H, Lumley JL (1972) A first course in turbulence. MIT press, Cambridge
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Agrawal, A. Measurement of spectrum with particle image velocimetry. Exp Fluids 39, 836–840 (2005). https://doi.org/10.1007/s00348-005-0018-4
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DOI: https://doi.org/10.1007/s00348-005-0018-4