Opposite effects of flame-generated potential and solenoidal velocity fluctuations on flame surface area in moderately intense turbulence
Artikel i vetenskaplig tidskrift, 2024

To explore the influence of dilatational and rotational motions on iso-scalar surface area within a premixed turbulent flame, three-dimensional compressible direct numerical simulation data obtained by Dave et al. (Combust. Flame 196 (2018) 386-399) from a lean, complex-chemistry, hydrogen-air flame propagating in intense small-scale turbulence (a ratio of laminar flame thickness to Kolmogorov length scale is about 20) in a box are analyzed using Helmholtz-Hodge decomposition of velocity field into solenoidal and potential components. The obtained results indicate that the flame surface area is created by potential velocity fluctuations generated due to combustion-induced thermal expansion, whereas the rotational motion acts to smooth wrinkles of iso-scalar surfaces within local preheat and reaction zones and, consequently, to reduce the flame surface area. The latter finding challenges the classical concept of flame-generated turbulence and is attributed to flame-generated solenoidal velocity fluctuations. Specifically, the incoming tangential (to the flame) vorticity is suppressed by baroclinic torque, which also generates vorticity in another tangential direction, with the latter (flame-generated) solenoidal velocity fluctuations working to smooth the flame surface. Thus, even under conditions of moderately intense turbulence, flame surface area can primarily be created by potential velocity perturbations caused by combustion-induced thermal expansion.

Helmholtz-Hodge de composition

Strain rate

Burning velocity


Flame speed

Flame surface area


Andrei Lipatnikov

Chalmers, Mekanik och maritima vetenskaper, Energiomvandling och framdrivningssystem

Vladimir Sabelnikov

ONERA Centre de Palaiseau

Nikolay V. Nikitin

Moscow State University

Proceedings of the Combustion Institute

1540-7489 (ISSN)

Vol. 40 1-4 105238

Modellering av turbulent förbränning av magra kolfria blandningar

Vetenskapsrådet (VR) (2023-04407), 2024-01-01 -- 2027-12-31.




Grundläggande vetenskaper


Strömningsmekanik och akustik



Mer information

Senast uppdaterat