Hostname: page-component-848d4c4894-xfwgj Total loading time: 0 Render date: 2024-06-21T06:30:01.487Z Has data issue: false hasContentIssue false

Dynamics and decay of a spherical region of turbulence in free space

Published online by Cambridge University Press:  27 November 2020

Ke Yu*
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA91125, USA
Tim Colonius
Affiliation:
Department of Mechanical and Civil Engineering, California Institute of Technology, Pasadena, CA91125, USA
D. I. Pullin
Affiliation:
Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA91125, USA
Grégoire Winckelmans
Affiliation:
Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Louvain-la-Neuve, Belgium
*
Email address for correspondence: kyu2@caltech.edu

Abstract

We perform direct numerical simulation and large-eddy simulation of an initially spherical region of turbulence evolving in free space. The computations are performed with a lattice Green's function method, which allows the exact free-space boundary conditions to be imposed on a compact vortical region. Large-eddy simulations are conducted with the stretched vortex subgrid stress model. The initial condition is spherically windowed, isotropic homogeneous incompressible turbulence. We study the spectrum and statistics of the decaying turbulence and compare the results with decaying isotropic turbulence, including cases representing different low-wavenumber behaviour of the energy spectrum (i.e. $k^2$ versus $k^4$). At late times the turbulent sphere expands with both mean radius and integral scale showing similar timewise growth exponents. The low-wavenumber behaviour has little effect on the inertial scales, and we find that decay rates follow the predictions of Saffman (J. Fluid Mech., vol. 27, 1967, pp. 581–593) in both cases, at least until approximately $400$ initial eddy turnover times. The boundary of the spherical region develops intermittency and features ejections of vortex rings. These are shown to occur at the integral scale of the initial turbulence field and are hypothesized to occur due to a local imbalance of impulse on this scale.

Type
JFM Papers
Copyright
© The Author(s), 2020. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press.Google Scholar
Batchelor, G. K. & Proudman, I. 1956 The large-scale structure of homogeneous turbulence. Phil. Trans. R. Soc. Lond. A 248, 369405.Google Scholar
Cantwell, B. J. 1986 Viscous starting jets. J. Fluid Mech. 173, 159189.CrossRefGoogle Scholar
Chasnov, J. R. 1995 The decay of axisymmetric homogeneous turbulence. Phys. Fluids 7, 600605.CrossRefGoogle Scholar
Cheng, W., Pullin, D. I. & Samtaney, R. 2020 Large-eddy simulation and modelling of Taylor–Couette flow. J. Fluid Mech. 890, A17.CrossRefGoogle Scholar
Cheng, W., Pullin, D. I. & Samtaney, R. 2018 Large-eddy simulation of flow over a grooved cylinder up to transcritical Reynolds numbers. J. Fluid Mech. 835, 327362.CrossRefGoogle Scholar
Cheng, W., Pullin, D. I., Samtaney, R., Zhang, W. & Gao, W. 2017 Large-eddy simulation of flow over a cylinder with $Re_{D}$ from $3.9\times 10^{3}$ to $8.5\times 10^{5}$: a skin-friction perspective. J. Fluid Mech. 820, 121158.CrossRefGoogle Scholar
Chung, D. & Pullin, D. I. 2009 Large-eddy simulation and wall modelling of turbulent channel flow. J. Fluid Mech. 631, 281309.CrossRefGoogle Scholar
Chung, D. & Pullin, D. I. 2010 Direct numerical simulation and large-eddy simulation of stationary buoyancy-driven turbulence. J. Fluid Mech. 643, 279308.CrossRefGoogle Scholar
Da Silva, C. B., Taveira, R. R. & Borrell, G. 2014 Characteristics of the turbulent/nonturbulent interface in boundary layers, jets and shear-free turbulence. J. Phys.: Conf. Ser. 506, 012015.Google Scholar
Davidson, P. A. 2010 On the decay of Saffman turbulence subject to rotation, stratification or an imposed magnetic field. J. Fluid Mech. 663, 268292.CrossRefGoogle Scholar
Huang, M. 1994 Theoretical and computational studies of isotropic homogeneous turbulence. PhD thesis, California Institute of Technology.Google Scholar
Ishida, T., Davidson, P. A. & Kaneda, Y. 2006 On the decay of isotropic turbulence. J. Fluid Mech. 564, 455475.CrossRefGoogle Scholar
Kambe, T. & Oshima, Y. 1975 Generation and decay of viscous vortex rings. J. Phys. Soc. Japan 38, 271280.CrossRefGoogle Scholar
Kolmogorov, A. N. 1962 A refinement of previous hypotheses concerning the local structure of turbulence in a viscous incompressible fluid at high Reynolds number. J. Fluid Mech. 13, 8285.CrossRefGoogle Scholar
Leonard, A. 1985 Computing three-dimensional incompressible flows with vortex elements. Annu. Rev. Fluid Mech. 17, 523559.CrossRefGoogle Scholar
Lim, T. T. & Nickels, T. B. 1992 Instability and reconnection in the head-on collision of two vortex rings. Nature 357, 225227.CrossRefGoogle Scholar
Liska, S. & Colonius, T. 2014 A parallel fast multipole method for elliptic difference equations. J. Comput. Phys. 278, 7691.CrossRefGoogle Scholar
Liska, S. & Colonius, T. 2016 A fast lattice Green's function method for solving viscous incompressible flows on unbounded domains. J. Comput. Phys. 316, 360384.CrossRefGoogle Scholar
Loitsyansky, L. G. 1939 Some basic laws of isotropic turbulence. Trudy Tsentr. Aero.-Giedrodin. Inst. 440, 323.Google Scholar
Lombardini, M., Pullin, D. I. & Meiron, D. 2014 Turbulent mixing driven by spherical implosions. Part 2. Turbulence statistics. J. Fluid Mech. 748, 113142.CrossRefGoogle Scholar
Lundgren, T. S. 1982 Strained spiral vortex model for turbulent fine structure. Phys. Fluids 25, 21932203.CrossRefGoogle Scholar
Mathew, J. & Basu, A. J. 2002 Some characteristics of entrainment at a cylindrical turbulence boundary. Phys. Fluids 14, 20652072.CrossRefGoogle Scholar
Matsuzawa, T., Mitchell, N., Perrard, S. & Irvine, W. 2019 Realization of confined turbulence through multiple vortex ring collisions. In APS Meeting Abstracts.Google Scholar
McKeown, R., Ostilla-Mónico, R., Pumir, A., Brenner, M. P. & Rubinstein, S. M. 2018 Cascade leading to the emergence of small structures in vortex ring collisions. Phys. Rev. Fluids 3, 124702.CrossRefGoogle Scholar
Misra, A. & Pullin, D. I. 1997 A vortex-based subgrid stress model for large-eddy simulation. Phys. Fluids 9 (8), 24432454.CrossRefGoogle Scholar
Phillips, O. M. 1956 The final period of decay of non-homogeneous turbulence. Proc. Camb. Phil. Soc. 252, 135151.CrossRefGoogle Scholar
Pope, S. B. 2001 Turbulent Flows. Cambridge University Press.Google Scholar
Saffman, P. G. 1967 The large-scale structure of homogeneous turbulence. J. Fluid Mech. 27, 581593.CrossRefGoogle Scholar
de Silva, C. M., Philip, J., Chauhan, K., Meneveau, C. & Marusic, I. 2013 Multiscale geometry and scaling of the turbulent-nonturbulent interface in high Reynolds number boundary layers. Phys. Rev. Lett. 111, 044501.CrossRefGoogle ScholarPubMed
Townsend, A. A. R. 1980 The Structure of Turbulent Shear Flow. Cambridge University Press.Google Scholar
Voelkl, T., Pullin, D. I. & Chan, D. C. 2000 A physical-space version of the stretched-vortex subgrid-stress model for large-eddy simulation. Phys. Fluids 12, 18101825.CrossRefGoogle Scholar
Winckelmans, G. S. 1995 Some progress in large-eddy simulation using the 3-D vortex particle method. CTR Annual Research Briefs, pp. 391–415.Google Scholar
Winckelmans, G. S. & Leonard, A. 1993 Contributions to vortex particle methods for the computation of three-dimensional incompressible unsteady flows. J. Comput. Phys. 109, 247273.CrossRefGoogle Scholar
Wolf, M., Holzner, M., Lüthi, B., Krug, D., Kinzelbach, W. & Tsinober, A. 2013 Effects of mean shear on the local turbulent entrainment process. J. Fluid Mech. 731, 95116.CrossRefGoogle Scholar