Helical turbulence: Turbulent viscosity and instability of the second moments

Belian, A.V.; Chkhetiani, О. G.; Golbraikh, E.; Moiseev, S. S.

doi:10.1016/s0378-4371(98)00212-x

Cited by 28 publications

(19 citation statements)

References 21 publications

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“…36 Several investigations have hypothesized that the rate of Kolmogorov spectrum formation is reduced by helicity, where a nonzero helicity partially inhibits the energy flux from larger to smaller scales. 2,36,48 Being turbulent viscosity one of the principal parameters connected with this energy flux, its magnitude should decrease with the decrease in direct energy cascade.…”

Section: Time Of Emission Of Particles Setmentioning

confidence: 99%

In Vivo Quantification of Helical Blood Flow in Human Aorta by Time-Resolved Three-Dimensional Cine Phase Contrast Magnetic Resonance Imaging

et al. 2008

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The mechanics of blood flow in arteries plays a key role in the health of individuals. In this framework, the role played by the presence of helical flow in the human aorta is still not clear in its relation to physiology and pathology. We report here a method for quantifying helical flow in vivo employing time-resolved cine phase contrast magnetic resonance imaging to obtain the complete spatio-temporal description of the three-dimensional pulsatile blood flow patterns in aorta. The method is applied to data of one healthy volunteer. Particle traces were calculated from velocity data: to them we applied a Lagrangian-based method for helical flow quantification, the Helical Flow Index, which has been developed and evaluated in silico in order to reveal global organization of blood flow. Our results: (i) put in evidence that the systolic hemodynamics in aorta is characterized by an evolving helical flow (we quantified a 24% difference in terms of the content of helicity in the streaming blood, between mid and early systole); (ii) indicate that in the first part of the systole helicity is ascrivable mainly to the asymmetry of blood flow in the left ventricle, joined with the laterality of the aorta. In conclusion, this study shows that the quantification of helical blood flow in vivo is feasible, and it might allow detection of anomalies in the expected physiological development of helical flow in aorta and accordingly, could be used in a diagnostic/prognostic index for clinical practice.

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Section: Time Of Emission Of Particles Setmentioning

confidence: 99%

In Vivo Quantification of Helical Blood Flow in Human Aorta by Time-Resolved Three-Dimensional Cine Phase Contrast Magnetic Resonance Imaging

et al. 2008

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“…Many properties of systems presenting helicity are related to the reduction of non-linear processes responsible for the transfer and redistribution of energy through various scales (the non-linear term in the Navier-Stokes equations actually diminishes when helicity exists). Several investigations have shown that the rate of Kolmogorov spectrum formation is reduced by helicity, where a non-zero helicity partially inhibits the energy flux from larger to smaller scales (Levich et al, 1991;Belian et al, 1998). Being turbulent viscosity one of the principal parameters connected with this energy flux, its magnitude should decrease with the decrease in direct energy cascade (Belian et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…To do this, we referred to the properties of Beltrami flows (Beltrami, 1889), proven to be useful in fluid mechanics, astrophysics and plasma physics (Belian et al, 1998;Arnold, 1978). The peculiarity of Beltrami flows is that their flow fields correspond to a state of maximum kinetic helicity, for a given total kinetic energy.…”

Section: Introductionmentioning

confidence: 99%

A mathematical description of blood spiral flow in vessels: application to a numerical study of flow in arterial bending

Grigioni

Daniele

Morbiducci

et al. 2005

Journal of Biomechanics

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“…Helicity is the pseudoscalar quantity hence it can be easily understood, that its influence appears only in quadratic and higher terms of perturbation theory or in the combination with another pseudoscalar quantities (e.g., large-scale helicity). Really, simultaneous consideration of memory effects and second order approximation indicate effective influence of helicity on turbulent viscosity [43] and turbulent diffusivity [40,44,45] already in the limit of small or infinite correlation time.…”

Section: Introductionmentioning

confidence: 99%

The influence of helicity on scaling regimes in the extended Kraichnan model

Chkhetiani

Hnatich

Jurčišinová

et al. 2006

J. Phys. A: Math. Gen.

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Abstract. We have investigated the advection of a passive scalar quantity by incompressible helical turbulent flow in the frame of extended Kraichnan model. Turbulent fluctuations of velocity field are assumed to have the Gaussian statistics with zero mean and defined noise with finite time-correlation. Actual calculations have been done up to two-loop approximation in the frame of field-theoretic renormalization group approach. It turned out that space parity violation (helicity) of turbulent environment does not affect anomalous scaling which is peculiar attribute of corresponding model without helicity. However, stability of asymptotic regimes, where anomalous scaling takes place, strongly depends on the amount of helicity. Moreover, helicity gives rise to the turbulent diffusivity, which has been calculated in one-loop approximation.

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Helical turbulence: Turbulent viscosity and instability of the second moments

Cited by 28 publications

References 21 publications

In Vivo Quantification of Helical Blood Flow in Human Aorta by Time-Resolved Three-Dimensional Cine Phase Contrast Magnetic Resonance Imaging

In Vivo Quantification of Helical Blood Flow in Human Aorta by Time-Resolved Three-Dimensional Cine Phase Contrast Magnetic Resonance Imaging

A mathematical description of blood spiral flow in vessels: application to a numerical study of flow in arterial bending

The influence of helicity on scaling regimes in the extended Kraichnan model

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