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The effect of swirl, premixedness and geometry has been investigated for hydrogen enriched premixed flame using Large Eddy Simulation (LES) with a Thickened Flame (TF) model. Swirl strength has been varied to study the effects of swirl on…

Fluid Dynamics · Physics 2021-02-11 Ashoke De , Sumanta Acharya

This paper presents an experimental analysis of flame-induced enstrophy transport in premixed swirl combustion at Karlovitz numbers between 20-50. Such flames posses a large-scale pressure field that -- in addition to the pressure fields…

Fluid Dynamics · Physics 2020-09-02 Askar Kazbekov , Adam M. Steinberg

By using a formulation of a class of compressible viscous flows with a heat source via vorticity and expansion-rate, we study the Oberbeck-Boussinesq flows. To this end we establish a new integral representation for solutions of parabolic…

Analysis of PDEs · Mathematics 2024-10-07 Zihao Guo , Zhongmin Qian , Zihao Shen

The foundations of gyrokinetic theory are reviewed with an emphasis on the applications of Lagrangian and Hamiltonian methods used in the derivation of nonlinear gyrokinetic Vlasov-Maxwell equations. These reduced dynamical equations…

Plasma Physics · Physics 2007-05-23 Alain J. Brizard

Propagation of weakly stretched spherical flames in partially pre-vaporized fuel sprays is theoretically investigated in this work. A general theory is developed to describe flame propagation speed, flame temperature, droplet evaporation…

Fluid Dynamics · Physics 2021-02-03 Qiang Li , Huangwei Zhang , Chang Shu

Although the evolution of premixed flames in turbulence has been frequently studied, it is not well understood how small flames interact with large-scale turbulent flow motion. Since this question is of practical importance for the…

Fluid Dynamics · Physics 2020-02-04 Tobias Falkenstein , Seongwon Kang , Heinz Pitsch

We study the evolution of a reactive field advected by a one-dimensional compressible velocity field and subject to an ignition-type nonlinearity. In the limit of small molecular diffusivity the problem can be described by a spatially…

Statistical Mechanics · Physics 2009-11-13 S. Berti , D. Vergni , A. Vulpiani

Given the need to develop zero-carbon combustors for power and aircraft engine applications, $S_d$ of a turbulent premixed flame, especially for H$_2$-air, is of immediate interest. The present study investigates 3D DNS cases of premixed…

The problem of burning of high-velocity gas streams in channels is revisited. Previous treatments of this issue are found to be incomplete. It is shown that despite relative smallness of the transversal gas velocity, it plays crucial role…

Fluid Dynamics · Physics 2015-05-13 Kirill A. Kazakov

We investigate the diffusive scaling of the Lorentz gas in the presence of an external force of mean-field type. In the weak coupling regime and for diffusive time scales, the test particle's law converges to the probability density…

Mathematical Physics · Physics 2024-11-07 Dominik Nowak

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

The fractal scaling properties of turbulent premixed flame fronts have been investigated and considered for modelling sub-grid scales in the Large-Eddy-Simulation framework. Since the width of such thin reaction fronts cannot be resolved…

Fluid Dynamics · Physics 2017-02-17 Francesco Battista , Guido Troiani , Francesco Picano

Premixed flames are susceptible to hydrodynamic and thermodiffusive instabilities that wrinkle the flame front and lead to complex multiscale patterns. They strongly impact the flame propagation and dynamics, increasing the speed of a…

Combustion stabilization and enhancement of the flammability limits are mandatory objectives to improve nowadays combustion chambers. At this purpose, the use of an electric field in the flame region provides a solution which is, at the…

Fluid Dynamics · Physics 2017-12-13 M. Di Renzo , P. De Palma , M. D. de Tullio , G. Pascazio

This study presents methane-air counterflow simulations, in computationally efficient similar form, allowing combustible mixtures to flow from one or both directions in order to learn more about multi-branched propagating flame structures…

Fluid Dynamics · Physics 2020-07-22 Claudia-F. López-Cámara , Albert Jordà Juanós , William A. Sirignano

We present a simulation scheme for discrete-velocity gases based on {\em local thermodynamic equilibrium}. Exploiting the kinetic nature of discrete-velocity gases, in that context, results in a natural splitting of fluxes, and the…

comp-gas · Physics 2008-02-03 Balu Nadiga , Dale Pullin

We use the recently derived density of states for a particle confined to a spherical well in three dimensional fuzzy space to compute the thermodynamics of a gas of non-interacting fermions confined to such a well. Special emphasis is…

High Energy Physics - Theory · Physics 2016-01-20 F. G. Scholtz , J. N. Kriel , H. W. Groenewald

We review some recent results concerning the derivation of the diffusion equation and the validation of Fick's law for the microscopic model given by the random Lorentz Gas. These results are achieved by using a linear kinetic equation as…

Mathematical Physics · Physics 2016-08-30 Alessia Nota

Combustion instabilities are a major concern in the design of Liquid Rocket Engines (LREs) and gas turbines. During this PhD work, several directions were explored to understand and mitigate their effects. First, more efficient and robust…

Fluid Dynamics · Physics 2021-03-02 Charlelie Laurent

We consider flame front propagation in channel geometries. The steady state solution in this problem is space dependent, and therefore the linear stability analysis is described by a partial integro-differential equation with a space…

Pattern Formation and Solitons · Physics 2011-08-19 Oleg Kupervasser , Zeev Olami , Itamar Procaccia