A direct Biot-Savart integration is used to decompose the strain rate into its local and nonlocal constituents, allowing the vorticity alignment with the local and nonlocal strain rate eigenvectors to be investigated. These strain rate tensor constituents are evaluated in a turbulent flow using data from highly resolved direct numerical simulations. While the vorticity aligns preferentially with the intermediate eigenvector of the combined strain rate, as has been observed previously, the present results, for the first time, clearly show that the vorticity aligns with the most extensional eigenvector of the nonlocal strain rate. This, in turn, reveals a significant linear contribution to the vortex stretching dynamics in turbulent flows.
REFERENCES
1.
Wm. T.
Ashurst
, A. R.
Kerstein
, R. M.
Kerr
, and C. H.
Gibson
, “Alignment of vorticity and scalar gradient with strain rate in simulated Navier–Stokes turbulence
,” Phys. Fluids
30
, 2343
(1987
).2.
A.
Tsinober
, An Informal Introduction to Turbulence
(Kluwer
, Dordrecht
, 2001
).3.
L. K.
Su
and W. J. A.
Dahm
, “Scalar imaging velocimetry measurements of the velocity gradient tensor field in turbulent flows. II. Experimental results
,” Phys. Fluids
8
, 1883
(1996
).4.
J.
Schumacher
, K. R.
Sreenivasan
, and V.
Yakhot
, “Asymptotic exponents from low-Reynolds-number flows
,” New J. Phys.
9
, 89
(2007
).5.
J. A.
Mullin
and W. J. A.
Dahm
, “Dual-plane stereo particle image velocimetry measurements of velocity gradient tensor fields in turbulent shear flow. II. Experimental results
,” Phys. Fluids
18
, 035102
(2006
).6.
A.
Tsinober
, E.
Kit
, and T.
Dracos
, “Experimental investigation of the field of velocity gradients in turbulent flows
,” J. Fluid Mech.
242
, 169
(1992
).7.
K.
Ohkitani
and S.
Kishiba
, “Nonlocal nature of vortex stretching in an inviscid fluid
,” Phys. Fluids
7
, 411
(1995
).8.
K. K.
Nomura
and G. K.
Post
, “The structure and dynamics of vorticity and rate of strain in incompressible homogeneous turbulence
,” J. Fluid Mech.
377
, 65
(1998
).9.
P. E.
Hamlington
, J.
Schumacher
, and W. J. A.
Dahm
, “Local and nonlocal strain rate fields and vorticity alignment in turbulent flows
,” Phys. Rev. E
77
, 026303
(2008
).10.
Z. S.
She
, E.
Jackson
, and S. A.
Orszag
, “Structure and dynamics of homogeneous turbulence: Models and simulations
,” Proc. R. Soc. London, Ser. A
434
, 101
(1991
).11.
J.
Jimenez
, A. A.
Wray
, P. G.
Saffman
, and R. S.
Rogallo
, “The structure of intense vorticity in isotropic turbulence
,” J. Fluid Mech.
255
, 65
(1993
).12.
J.
Jimenez
, “Kinematic alignment effects in turbulent flows
,” Phys. Fluids A
4
, 652
(1992
).13.
K. A.
Buch
and W. J. A.
Dahm
, “Experimental study of the fine-scale structure of conserved scalar mixing in turbulent shear flows. Part 1.
,” J. Fluid Mech.
317
, 21
(1996
).© 2008 American Institute of Physics.
2008
American Institute of Physics
You do not currently have access to this content.
