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Diffusive transport of mass occurs at small scales in turbulent premixed flames. As a result, multicomponent mass diffusion, which is often neglected in direct numerical simulations (DNS) of premixed combustion, has the potential to impact…

Fluid Dynamics · Physics 2022-07-20 Aaron J. Fillo , Peter E. Hamlington , Kyle E. Niemeyer

In the present study, we conduct direct numerical simulations of two-way force-coupled particle-laden compressible turbulent boundary layers at the free-stream Mach number of 2.0 for the purpose of examining the effects of particles on the…

Fluid Dynamics · Physics 2024-07-01 Ming Yu , Yibin Du , Qian Wang , Siwei Dong , Xianxu Yuan

Propagation of turbulent premixed flames influenced by the intrinsic hydrodynamic flame instability (the Darrieus-Landau instability) is considered in a two-dimensional case using the model nonlinear equation proposed recently. The…

Mathematical Physics · Physics 2012-11-27 Maxim Zaytsev , Vitaliy Bychkov

The proliferation of turbulence in subcritical wall-bounded shear flows involves spatially localised coherent structures. Turbulent spots correspond to finite-time nonlinear responses to pointwise disturbances and are regarded as seeds of…

Fluid Dynamics · Physics 2020-10-14 Pavan V. Kashyap , Yohann Duguet , Matthew Chantry

Liquid-infused surfaces (LIS) can reduce friction drag in both laminar and turbulent flows. However, the heat transfer properties of such multi-phase surfaces have still not been investigated to a large extent. We use numerical simulations…

Fluid Dynamics · Physics 2022-05-11 Johan Sundin , Umberto Ciri , Stefano Leonardi , Marcus Hultmark , Shervin Bagheri

We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…

Astrophysics · Physics 2011-02-11 David Arnett , Casey Meakin , P. A. Young

This work is dedicated to the analysis of the delicate details of the effect of upstream velocity fluctuations on the flame propagation speed. The investigation was carried out using the Sivashinsky model of cellularisation of…

Fluid Dynamics · Physics 2013-05-29 V. Karlin

We study the dynamics of thermonuclear flames propagating in fuel stirred by stochastic forcing. The fuel consists of carbon and oxygen in a state which is encountered in white dwarfs close to the Chandrasekhar limit. The level set method…

Astrophysics · Physics 2015-06-24 W. Schmidt , W. Hillebrandt , J. C. Niemeyer

The turbulent flow of a fluid carrying trace amounts of a condensable species through a differentially cooled vertical channel geometry is simulated using single-phase direct numerical simulations. The release of latent heat during…

Fluid Dynamics · Physics 2020-01-28 Philipp Bahavar , Claus Wagner

The multiscale nature of turbulent combustion necessitates accurate and computationally efficient methods for direct numerical simulations (DNS). The field has long been dominated by high-order finite differences, which lack the flexibility…

Fluid Dynamics · Physics 2024-01-24 Jack R. C. King

Lean premixed hydrogen-air flames are strongly affected by thermodiffusive (TD) instabilities, which can alter the flame structure and enhance the local reactivity many-fold. Two recent models (Howarth et al. (Combust.~Flame 253, 2023) and…

A theoretical analysis is developed to investigate the effects of gas expansion due to heat release on unsteady diffusion flames evolving in a pipe flow in which the mixing of reactants is controlled by Taylor's dispersion processes thereby…

Fluid Dynamics · Physics 2024-07-03 Prabakaran Rajamanickam , Adam D. Weiss

A study of a reacting boundary layer flow with heat transfer at conditions typical for configurations at elevated pressures has been performed using a set of direct numerical simulations. Effects of wall temperatures are investigated,…

Fluid Dynamics · Physics 2021-02-16 Nikolaos Perakis , Oskar Haidn , Matthias Ihme

A series of numerical simulations of Rayleigh-B{\'e}nard convection in a cubic cavity are conducted in order to examine the structure of the thermal boundary layer in case of mixed boundary conditions. The main goal of the study is the…

Fluid Dynamics · Physics 2020-10-29 Andrei Sukhanovskii , Andrei Vasiliev

Turbulent flows in the solar wind, large scale current sheets, multiple current sheets, and shock waves lead to the formation of environments in which a dense network of current sheets is established and sustains "turbulent reconnection".…

Solar and Stellar Astrophysics · Physics 2016-08-17 Loukas Vlahos , Theophilos Pisokas , Heinz Isliker , Vassilios Tsiolis , Anastasios Anastasiadis

Supersonic lean premixed hydrogen/air combustion stabilised by a cavity-flame holder within a model scramjet, characterized by a Mach 1.5 inflow at 1000 K and 50 kPa, is investigated via direct numerical simulation. By separately…

Fluid Dynamics · Physics 2025-01-07 Minqi Lin , Jian Fang , Xi Deng , Xiaojun Gu , Zhi X. Chen

The plasmoid-induced-reconnection model explaining solar flares based on bursty reconnection produced by an ejecting plasmoid suggests a possible relation between the ejection velocity of a plasmoid and the rate of magnetic reconnection. In…

Pore-resolved direct numerical simulations of turbulent open channel flow are performed comparing the structure and dynamics of turbulence over impermeable rough and smooth walls to a porous sediment bed at permeability Reynolds number…

Fluid Dynamics · Physics 2022-05-02 Shashank K. Karra , Sourabh V. Apte , Xiaoliang He , Timothy D. Scheibe

We present a systematic numerical study of the effect of turbulent velocity fluctuations on the thermal pressure distribution in thermally bistable flows. The simulations employ a random turbulent driving generated in Fourier space rather…

Astrophysics · Physics 2009-11-11 Adriana Gazol , Enrique Vazquez-Semadeni , Jongsoo Kim

Ultra-lean premixed hydrogen combustion is a possible solution to decarbonize industry, while limiting flame temperatures and thus nitrous oxide emissions. These lean hydrogen/air flames experience strong preferential diffusion effects,…

Computational Physics · Physics 2025-08-13 Stijn N. J. Schepers , Jeroen A. van Oijen