Improved boundary conditions for the direct numerical simulation of turbulent subsonic flows. I. Inviscid flows

Prosser, Robert

doi:10.1016/j.jcp.2005.01.027

Cited by 34 publications

(43 citation statements)

References 31 publications

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“…For the simple case of a pure outflow boundary without strong transverse gradients or reacting species, all but the first of the terms in (14) may be omitted with an acceptable loss of accuracy. The importance of including transverse convection terms for highly turbulent flows, even without flame-boundary interaction, has been noted previously by Prosser [19] and Yoo and Im [16]. In configurations where the flame passes through the boundary, Sutherland and Kennedy [20] have demonstrated the importance of including the source term in order to avoid large pressure perturbations which can have a significant effect on the interior solution.…”

Section: Boundary Conditionsmentioning

confidence: 76%

Geometrical Properties and Turbulent Flame Speed Measurements in Stationary Premixed V-flames Using Direct Numerical Simulation

Dunstan

Swaminathan

Bray

et al. 2010

Flow Turbulence Combust

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Three dimensional, fully compressible direct numerical simulations (DNS) of premixed turbulent flames are carried out in a V-flame configuration. The governing equations and the numerical implementation are described in detail, including modifications made to the Navier-Stokes Characteristic Boundary Conditions (NSCBC) to accommodate the steep transverse velocity and composition gradients generated when the flame crosses the boundary. Three cases, at turbulence intensities, u /s L , of 1, 2, and 6 are considered. The influence of the flame holder on downstream flame properties is assessed through the distributions of the surfaceconditioned displacement speed, curvature and tangential strain rates, and compared to data from similarly processed planar flames. The distributions are found to be indistinguishable from planar flames for distances greater than about 17δ th downstream of the flame holder, where δ th is the laminar flame thermal thickness. Favre mean fields are constructed, and the growth of the mean flame brush is found to be well described by simple Taylor type diffusion. The turbulent flame speed, s T is evaluated from an expression describing the propagation speed of an isosurface of the mean reaction progress variablec in terms of the imbalance between the mean reactive, diffusive, and turbulent fluxes within the flame brush. The results are compared to the consumption speed, s C , calculated from the integral of the mean reaction rate, and to the predictions of a recently developed flame speed model (Kolla et al., Combust Sci Technol 181(3):518-535, 2009). The model predictions are improved in all cases by including the effects of mean molecular diffusion, and the overall agreement is good for the higher turbulence intensity cases once the tangential convective flux ofc is taken into account.

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Section: Boundary Conditionsmentioning

confidence: 76%

Geometrical Properties and Turbulent Flame Speed Measurements in Stationary Premixed V-flames Using Direct Numerical Simulation

Dunstan

Swaminathan

Bray

et al. 2010

Flow Turbulence Combust

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“…In contrast to the approaches of Prosser [24,25] and Im et al [26,27] in the context of 1-D characteristics for low Mach number flows, the proposed method is valid for general flows in addition to acoustic waves. Our approach is based on the rigorous mathematical analysis for general flows, which is consistent with the flow physics.…”

Section: Resultsmentioning

confidence: 91%

“…The LODI and other approaches generate strong pressure reflections and distortion without vorticity reflection. Prosser [24] applied the improved LODI approach to obtain slight pressure reflection and distortion for very low Mach number flows, when vortices cross the boundary. It is not a surprise that both 1-D and multidimensional characteristic boundary conditions do not generate the spurious reflection for vorticity.…”

Section: Flow Around Cylindermentioning

confidence: 99%

“…This treatment allows flame propagation through the boundary without drastically affecting the solution on the interior. Prosser [24,25] improved LODI approach for low Mach number flows using asymptotic analysis. Yoo et al [26] and Yoo and Im [27] improved the LODI approach by incorporating the transverse terms to the characteristic wave amplitudes and by accommodating a relaxation treatment for the transverse gradient terms.…”

Section: Introductionmentioning

confidence: 99%

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Nonreflecting boundary conditions based on nonlinear multidimensional characteristics

Liu¹,

Vasilyev²

2009

Numerical Methods in Fluids

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SUMMARYNonlinear characteristic boundary conditions based on nonlinear multidimensional characteristics are proposed for 2-and 3-D compressible Navier-Stokes equations with/without scalar transport equations. This approach is consistent with the flow physics and transport properties. Based on the theory of characteristics, which is a rigorous mathematical technique, multidimensional flows can be decomposed into acoustic, entropy, and vorticity waves. Nonreflecting boundary conditions are derived by setting corresponding characteristic variables of incoming waves to zero and by partially damping the source terms of the incoming acoustic waves. In order to obtain the resulting optimal damping coefficient, analysis is performed for problems of pure acoustic plane wave propagation and arbitrary flows. The proposed boundary conditions are tested on two benchmark problems: cylindrical acoustic wave propagation and the wake flow behind a cylinder with strong periodic vortex convected out of the computational domain. This new approach substantially minimizes the spurious wave reflections of pressure, density, temperature, and velocity as well as vorticity from the artificial boundaries, where strong multidimensional flow effects exist. The numerical simulations yield accurate results, confirm the optimal damping coefficient obtained from analysis, and verify that the method substantially improves the 1-D characteristics-based nonreflecting boundary conditions for complex multidimensional flows.

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“…The treatment of the boundary conditions (BCs) has also been a subject of intense research [19][20][21][22][23][24] since it can dramatically deteriorate both the accuracy and robustness of the calculations. Non-reflecting BCs based on characteristic treatment (wave analysis at boundaries) have been developed and are now commonly used to model inlets and outlets of the computational domain and their influence on acoustics is now well identified [25][26][27][28]. Despite the proven effectiveness of characteristic formulations, walls are still often represented with Dirichlet BCs, where the velocity is set to zero and density at the wall is obtained either using the continuity equation without characteristic treatment or specifying a zero pressure gradient.…”

Section: Introductionmentioning

confidence: 99%

On the stability and dissipation of wall boundary conditions for compressible flows

Lamarque

Porta

Nicoud

et al. 2009

Numerical Methods in Fluids

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International audienceCharacteristic formulations for boundary conditions have demonstrated their effectiveness to handle inlets and outlets, especially to avoid acoustic wave reflections. At walls, however, most authors use simple Dirichlet or Neumann boundary conditions, where the normal velocity (or pressure gradient) is set to zero. This paper demonstrates that there are significant differences between characteristic and Dirichlet methods at a wall and that simulations are more stable when using walls modelled with a characteristic wave decomposition. The derivation of characteristic methods yields an additional boundary term in the continuity equation, which explains their increased stability. This term also allows to handle the two acoustic waves going towards and away from the wall in a consistent manner. Those observations are confirmed by stability matrix analysis and one- and two-dimensional simulations of acoustic modes in cavities

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Improved boundary conditions for the direct numerical simulation of turbulent subsonic flows. I. Inviscid flows

Cited by 34 publications

References 31 publications

Geometrical Properties and Turbulent Flame Speed Measurements in Stationary Premixed V-flames Using Direct Numerical Simulation

Geometrical Properties and Turbulent Flame Speed Measurements in Stationary Premixed V-flames Using Direct Numerical Simulation

Nonreflecting boundary conditions based on nonlinear multidimensional characteristics

On the stability and dissipation of wall boundary conditions for compressible flows

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