• Publications
  • Influence
Persistent small scale anisotropy in homogeneous shear flows.
  • Pumir, Shraiman
  • Physics, Medicine
  • Physical review letters
  • 23 October 1995
Numerical simulation of interacting vortex tubes.
  • Pumir, Kerr
  • Physics, Medicine
  • Physical review letters
  • 20 April 1987
TLDR
The structure of the cores of interacting vortex tubes in three-dimensional incompressible hydrodynamics has been simulated by a pseudospectral method and at higher Reynolds numbers, the core tends to flatten, suggesting the formation of vortex ribbons. Expand
Shape selection of Saffman-Taylor fingers.
TLDR
An expansion beyond all orders leading to the formulation of a nonlinear eigenvalue problem with a discrete set of solutions is explained, predicting that the relative width of the finger tends to 1 2 as the surface tension to the power 2 3. Expand
Exponential tails and random advection.
Simple models of non-Gaussian statistics for a turbulently advected passive scalar.
  • Holzer, Pumir
  • Mathematics, Medicine
  • Physical review. E, Statistical physics, plasmas…
  • 1993
TLDR
This work studies the probability distribution of a passive scalar undergoing turbulent mixing in the presence of a mean scalar gradient and considers a simplified version of the Kerstein model which is analytically fully tractable and gives qualitatively similar results numerically. Expand
Analytic theory of the Saffman-Taylor fingers.
TLDR
A complete analytic solution is presented for the selection of symmetric Saffman-Taylor fingers, in the small\char21{}surface-tension limit, and two methods are proposed to extract the selection mechanism from this asymptotic series. Expand
Vortex morphology and Kelvin's theorem.
  • Pumir, Shraiman, Siggia
  • Physics, Medicine
  • Physical review. A, Atomic, molecular, and…
  • 1 April 1992
The Clebsch form of the Euler equations provides an intuitive picture as to how the circulation constraints direct the spatial organization of vorticity and favor the formation of vortex sheets.Expand
Finite-time singularities in the axisymmetric three-dimension Euler equations.
  • Pumir, Siggia
  • Physics, Medicine
  • Physical review letters
  • 9 March 1992
For pointlike singularities localized well away from the symmetry axis, axisymmetric flows with swirl are arbitrarily well approximated by two-dimensional Boussinesq convection. An adaptive meshExpand
Incipient singularities in the Navier-Stokes equations.
  • Siggia, Pumir
  • Physics, Medicine
  • Physical review letters
  • 21 October 1985
Infinite pointwise stretching in a finite time for general initial conditions is found in a simulation of the Biot-Savart equation for a slender vortex tube in three dimensions. Viscosity isExpand
Heat transport in a liquid layer locally heated on its free surface.
  • Pumir, Blumenfeld
  • Physics, Medicine
  • Physical review. E, Statistical physics, plasmas…
  • 1 November 1996
TLDR
A theoretical estimate of the temperature elevation when the fluid motion is laminar or turbulent, the weld pool surface remaining flat, follows the theoretical work of Shraiman and Siggia in Rayleigh-B\'enard convection. Expand
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