DNS study of the bending effect due to smoothing mechanism
Journal article, 2019

Propagation of either an infinitely thin interface or a reaction wave of a nonzero thickness in forced, constant-density, statistically stationary, homogeneous, isotropic turbulence is simulated by solving unsteady 3D Navier–Stokes equations and either a level set (G) or a reaction-diffusion
equation, respectively, with all other things being equal. In the case of the interface, the fully developed bulk consumption velocity normalized using the laminar-wave speed SL depends linearly on the normalized rms velocity u'/SL. In the case of the reaction wave of a nonzero thickness, dependencies of the normalized bulk consumption velocity on u'/SL show bending, with the effect being increased by a ratio of the laminar-wave thickness to the turbulence length scale. The obtained bending effect is controlled by a decrease in the rate of an increase AF in the reaction-zone-surface area with increasing u'/SL. In its turn, the bending of the AF(u'/SL)-curves stems from inefficiency of small-scale turbulent eddies in wrinkling the reaction-zone surface, because such small-scale wrinkles characterized by a high local curvature are smoothed out by molecular transport within the reaction wave.

turbulent reacting flows

bending effect

reaction surface area

molecular transport

reaction waves

turbulent consumption velocity

direct numerical simulations

Author

Rixin Yu

Lund University

Andrei Lipatnikov

Chalmers, Mechanics and Maritime Sciences, Combustion

Fluids

2311-5521 (eISSN)

Vol. 4 1 1-13 31

Roots

Basic sciences

Subject Categories

Fluid Mechanics and Acoustics

DOI

10.3390/fluids4010031

More information

Latest update

9/20/2019