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Updated: Mar 30, 2026

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp
Published on: February 3, 2014
Disentangling the triadic interactions in Navier-Stokes equations.
Ganapati Sahoo1, Luca Biferale2
1Department of Physics and INFN, University of Rome "Tor Vergata", Via della Ricerca Scientifica 1, 00133, Rome, Italy. ganapati.sahoo@gmail.com.
Investigating helicity in fluid dynamics, this study reveals how removing negative helical modes impacts energy transfer. Modifying wave numbers influences whether an inverse energy cascade or a transition from backward to forward transfer occurs.
Area of Science:
- Fluid Dynamics
- Turbulence Theory
- Nonlinear Dynamics
Background:
- Helicity plays a crucial role in energy transfer within turbulent flows.
- The Navier-Stokes equations, fundamental to fluid dynamics, are modified to break mirror symmetry and study helicity's effects.
- Understanding energy transfer mechanisms is key to predicting complex fluid behaviors.
Purpose of the Study:
- To investigate the influence of helicity on energy transfer dynamics in a modified Navier-Stokes system.
- To analyze how selective removal of helical modes affects fluid behavior.
- To determine the impact of wave number localization of helical modes on energy transfer patterns.
Main Methods:
- Modification of the Navier-Stokes equations to explicitly break mirror symmetry.
- Selective removal of negative helical Fourier modes at specific wave number shells.
- Analysis of energy transfer across different interaction classes based on helicity content.
- Varying the wave number of the localized helical modes relative to the forcing scale.
Main Results:
- An inverse energy cascade and stationary helical condensate form when negative helical modes are confined to wave numbers below the forcing scale.
- A transition from backward to forward energy transfer is observed when negative helical modes are localized above the forcing scale.
- The localization of helical modes significantly alters the direction and nature of energy transfer.
Conclusions:
- Helicity content and its spatial distribution are critical determinants of energy transfer direction in turbulent flows.
- The study demonstrates a mechanism for controlling energy cascade direction by manipulating helical modes.
- Findings offer insights into the fundamental processes governing energy transfer in asymmetric fluid systems.
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