The scalar filtered mass density function (FMDF) is further developed and employed for large-eddy simulations (LES) of high speed turbulent flows in complex geometries. LES/FMDF is implemented via an efficient, hybrid numerical method. In this method, the filtered compressible Navier-Stokes equations in curvilinear coordinate systems are solved with a generalized, high-order, multi-block, compact differencing scheme. Turbulent mixing and combustion are modeled with the FMDF. The LES/FMDF method is used for simulations of isotropic turbulent flow in a piston-cylinder assembly, the flow in a shock tube and a supersonic co-axial helium-air jet. The critical role of pressure in the FMDF equation when applied to compressible flows is studied. It is shown that LES/FMDF is reliable and is able to simulate compressible turbulent mixing and combustion in supersonic flows.

1 aLi, Z.1 aJaberi, F.A.1 aBanaeizadeh, A. uhttps://icer.msu.edu/research/publications/large-scale-simulations-supersonic-turbulent-reacting-flows01480nas a2200121 4500008004100000245008700041210006900128260003100197520098000228100001101208700001701219856012201236 2010 eng d00aNumerical Investigations of Shock-Turbulence Interactions in a Planar Mixing Layer0 aNumerical Investigations of ShockTurbulence Interactions in a Pl aOrlando, FLbAIAAc01/20103 aDirect numerical simulation (DNS) and large-eddy simulation (LES) of spatially developing supersonic mixing layer, interacting with an oblique shock wave are conducted with a new high-order Monotonicity-Preserving scheme. Without the incident shock, the mixing layer grows linearly and exhibits self-similar behavior after the transition. With the shock, significant small-scale turbulence is generated just behind the shock. With an increase in shock angle, the intensity of the shock-generated turbulence is increased and its peak position shifts away from the mixing layer centerline. The effects of turbulence on the shock are also shown to be very significant, such that normal shocklets and large adverse pressure gradients are created in some conditions. Comparison with the DNS data indicates that the LES with the modified kinetic energy viscosity (MKEV) subgrid stress model is able to predict the main features of the flow and shock-turbulence interactions.

1 aLi, Z.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/numerical-investigations-shock-turbulence-interactions-planar-mixing-layer01289nas a2200205 4500008004100000245006500041210006500106260001200171300001100183490000800194520066500202100001800867700001900885700002000904700001600924700001100940700001800951700002000969856009400989 2009 eng d00aConstraints on the Density Dependence of the Symmetry Energy0 aConstraints on the Density Dependence of the Symmetry Energy c03/2009 a1227010 v1023 aCollisions involving {112Sn} and {124Sn} nuclei have been simulated with the improved quantum molecular dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at subnormal density are obtained. The results from the present work are compared to constraints put forward in other recent analyses.

1 aTsang, M., B.1 aZhang, Yingxun1 aDanielewicz, P.1 aFamiano, M.1 aLi, Z.1 aLynch, W., G.1 aSteiner, A., W. uhttps://icer.msu.edu/research/publications/constraints-density-dependence-symmetry-energy01565nas a2200121 4500008004100000245005800041210005700099260007700156520108400233100001101317700001701328856009801345 2009 eng d00aLarge-Scale Simulations of High Speed Turbulent Flows0 aLargeScale Simulations of High Speed Turbulent Flows aOrlando, FLbAmerican Institute of Aeronautics and Astronauticsc01/20093 aThis paper briefly describes a new class of high-order Monotonicity-Preserving (MP) finite difference methods recently developed for direct numerical simulation (DNS) and large-eddy simulation (LES) of high-speed turbulent flows. The MP method has been implemented together with high-order compact (COMP) and weighted essentially non- oscillatory (WENO) methods in a generalized three-dimensional (3D) code and has been applied to various 1D, 2D and 3D problems. For the LES, compressible versions of the gradient-based subgrid-scale closures are employed. Detailed and extensive analysis of various flows indicates that MP schemes have less numerical dissipation and faster grid convergence than WENO schemes. Simulations conducted with high-order MP schemes preserve sharp changes in flow variables without spurious oscillations and capture the turbulence at the smallest simulated scales. The non-conservative form of the scalar equation solved with MP schemes are shown to generate the same results as COMP schemes for supersonic mixing problems involving shock waves.

1 aLi, Z.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/large-scale-simulations-high-speed-turbulent-flows00490nas a2200109 4500008004100000245007600041210006900117260005600186100001100242700001700253856011000270 2009 eng d00aA New Model for Numerical Simulations of Two-Phase Turbulent Combustion0 aNew Model for Numerical Simulations of TwoPhase Turbulent Combus aAnn Arbor, MIbNational Combustion Meetingc05/20091 aLi, Z.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/new-model-numerical-simulations-two-phase-turbulent-combustion01702nas a2200133 4500008004100000245007000041210006800111260001200179490000700191520123400198100001101432700001701443856010801460 2009 eng d00aTurbulence-Interface Interactions in a Two-Fluid Homogeneous Flow0 aTurbulenceInterface Interactions in a TwoFluid Homogeneous Flow c09/20090 v213 aThe two-way interactions between the turbulent velocity field and the interface in an incompressible two-fluid homogeneous turbulent flow are studied with a recently developed Lagrangian–Eulerian interfacial particle level-set method. The numerical results confirm that the rate of change of the interface area is directly related to the work done by the surface tension force. While the surface tension damps the surrounding turbulence in the “interface stretching period” to oppose the increase in interface area, it is shown to actually increase the turbulent kinetic energy when the interface experiences compression. Additionally, the surface tension force is found to generate strong vortical motions close to the interface through the baroclinic torque effects. There is also an increase in strain rate and the viscous dissipation rate of turbulent kinetic energy in the interface region. The effect of interface on the surrounding turbulence appears primarily in the direction perpendicular to the interface. Analysis of the vorticity and kinetic energy equations indicates that the turbulence-interface interactions are strongly dependent on the fluids’ density ratio and the Weber number.

1 aLi, Z.1 aJaberi, F.A. uhttps://icer.msu.edu/research/publications/turbulence-interface-interactions-two-fluid-homogeneous-flow01908nas a2200133 4500008004100000245008100041210006900122260003200191520138900223100001101612700001701623700001701640856011701657 2008 eng d00aFiltered Mass Density Function for Numerical Simulations of Spray Combustion0 aFiltered Mass Density Function for Numerical Simulations of Spra aReno, NevadabAIAAc01/20083 aThis paper briefly describes our recent efforts on the modeling and numerical simulations of two-phase turbulent reacting flows in realistic combustion systems with a new large-eddy simulation (LES) model. The model is constructed based on the two-phase extension of scalar filtered mass density function (FMDF) and a Lagrangian-Eulerian- Lagrangian mathematical/numerical methodology. In this methodology, the “resolved” fluid velocity field is obtained by solving the filtered form of the compressible Navier-Stokes equations with a high-order finite difference scheme. The liquid (droplet) phase and scalar (temperature and species mass fractions) fields are both obtained by stochastic Lagrangian models. There are two-way interactions between the phases and all the Eulerian and Lagrangian fields. The LES/FMDF is used for systematic analysis of turbulent combustion in the spray-controlled dump combustor and double-swirl spray burner for various flow and spray parameters. The effects of fuel type, spray angle, mass loading ratio, droplet size distribution, fuel/air composition, wall, and inflow/outflow conditions on the combustion are investigated. It has been found that the main features of the turbulence and combustion are modified by changing the inflow/outflow conditions. The LES/FMDF results also confirm the significance of the spray parameters.

1 aLi, Z.1 aJaberi, F.A.1 aYaldizli, M. uhttps://icer.msu.edu/research/publications/filtered-mass-density-function-numerical-simulations-spray-combustion02418nas a2200169 4500008004100000245011500041210006900156260001100225300001400236490000700250520174400257653007702001100001102078700001702089700001902106856012302125 2008 eng d00aA Hybrid Langrangian-Eulerian Particle-Level Set Method for numerical Simulations of Two-Fluid Turbulent Flows0 aHybrid LangrangianEulerian ParticleLevel Set Method for numerica c4/2008 a2271-23000 v563 aA coupled Lagrangian interface-tracking and Eulerian level set (LS) method is developed and implemented for numerical simulations of two-fluid flows. In this method, the interface is identified based on the locations of notional particles and the geometrical information concerning the interface and fluid properties, such as density and viscosity, are obtained from the LS function. The LS function maintains a signed distance function without an auxiliary equation via the particle-based Lagrangian re-initialization technique. To assess the new hybrid method, numerical simulations of several ‘standard interface-moving’ problems and two-fluid laminar and turbulent flows are conducted. The numerical results are evaluated by monitoring the mass conservation, the turbulence energy spectral density function and the consistency between Eulerian and Lagrangian components. The results of our analysis indicate that the hybrid particle-level set method can handle interfaces with complex shape change, and can accurately predict the interface values without any significant (unphysical) mass loss or gain, even in a turbulent flow. The results obtained for isotropic turbulence by the new particle-level set method are validated by comparison with those obtained by the ‘zero Mach number’, variable-density method. For the cases with small thermal/mass diffusivity, both methods are found to generate similar results. Analysis of the vorticity and energy equations indicates that the destabilization effect of turbulence and the stability effect of surface tension on the interface motion are strongly dependent on the density and viscosity ratios of the fluids. Copyright q 2007 John Wiley & Sons, Ltd.

10atwo-fluid turbulent flows; particle-level set method; interface tracking1 aLi, Z.1 aJaberi, F.A.1 aShih, T., I-P. uhttps://icer.msu.edu/research/publications/hybrid-langrangian-eulerian-particle-level-set-method-numerical-simulations01478nas a2200193 4500008004100000245010300041210006900144260001200213300001400225490000800239520081400247100001901061700002001080700001601100700001101116700001801127700001801145856012101163 2008 eng d00aThe influence of cluster emission and the symmetry energy on neutron-proton spectral double ratios0 ainfluence of cluster emission and the symmetry energy on neutron c02/2008 a145–1480 v6643 aThe emissions of neutrons, protons and bound clusters from central {124Sn} + {124Sn} and {112Sn} + {112Sn} collisions are simulated using the Improved Quantum Molecular Dynamics model for two different density-dependent symmetry-energy functions. The calculated neutron-proton spectral double ratios for these two systems are sensitive to the density dependence of the symmetry energy, consistent with previous work. Cluster emission increases the double ratios in the low energy region relative to values calculated in a coalescence-invariant approach. To circumvent uncertainties in cluster production and secondary decays, it is important to have more accurate measurements of the neutron-proton ratios at higher energies in the center of mass system, where the influence of such effects is reduced.

1 aZhang, Yingxun1 aDanielewicz, P.1 aFamiano, M.1 aLi, Z.1 aLynch, W., G.1 aTsang, M., B. uhttps://icer.msu.edu/research/publications/influence-cluster-emission-symmetry-energy-neutron-proton-spectral-double00522nas a2200121 4500008004100000050001900041245006500060210006400125260007800189100001700267700001100284856010500295 2008 eng d aAIAA 2008-115400aLarge Eddy Simulations of Two-Phase Turbulent Reacting Flows0 aLarge Eddy Simulations of TwoPhase Turbulent Reacting Flows aReno, NevadabAMERICAN INSTITUTE OF AERONAUTICS AND ASTRONAUTICSc01/20081 aJaberi, F.A.1 aLi, Z. uhttps://icer.msu.edu/research/publications/large-eddy-simulations-two-phase-turbulent-reacting-flows01888nas a2200133 4500008004100000245008100041210006900122260003200191520138900223100001701612700001101629700001701640856009701657 2007 eng d00aFiltered Mass Density Function for Numerical Simulations of Spray Combustion0 aFiltered Mass Density Function for Numerical Simulations of Spra aReno, NevadabAIAAc01/20083 aThis paper briefly describes our recent efforts on the modeling and numerical simulations of two-phase turbulent reacting flows in realistic combustion systems with a new large-eddy simulation (LES) model. The model is constructed based on the two-phase extension of scalar filtered mass density function (FMDF) and a Lagrangian-Eulerian- Lagrangian mathematical/numerical methodology. In this methodology, the “resolved” fluid velocity field is obtained by solving the filtered form of the compressible Navier-Stokes equations with a high-order finite difference scheme. The liquid (droplet) phase and scalar (temperature and species mass fractions) fields are both obtained by stochastic Lagrangian models. There are two-way interactions between the phases and all the Eulerian and Lagrangian fields. The LES/FMDF is used for systematic analysis of turbulent combustion in the spray-controlled dump combustor and double-swirl spray burner for various flow and spray parameters. The effects of fuel type, spray angle, mass loading ratio, droplet size distribution, fuel/air composition, wall, and inflow/outflow conditions on the combustion are investigated. It has been found that the main features of the turbulence and combustion are modified by changing the inflow/outflow conditions. The LES/FMDF results also confirm the significance of the spray parameters.

1 aYaldizli, M.1 aLi, Z.1 aJaberi, F.A. uhttps://icer.msu.edu/filtered-mass-density-function-numerical-simulations-spray-combustion-001300nas a2200133 4500008004100000245007900041210006900120260005000189520079100239100001701030700001101047700001701058856009101075 2007 eng d00aA New Model for Large Eddy Simulations of Multi-Phase Turbulent Combustion0 aNew Model for Large Eddy Simulations of MultiPhase Turbulent Com aCincinnati, OhiobAIAA/ASME/SAI/ASEEc07/20073 aNumerical simulations of a spray-controlled lean premixed dump combustor are con- ducted via a two-phase large eddy simulation (LES) methodology. In this methodology, the velocity field is obtained by a high-order finite difference method. The subgrid gas- liquid combustion closure is based on the two-phase filtered mass density function (FMDF) method and the spray is modeled with a Lagrangian scheme. The effects of spray, fuel/air composition, and inflow/outflow conditions on the combustion are investigated. It has been found that the main features of the turbulence and combustion inside the dump combustor are very differently modified by the spray for different spray parameters. The LES/FMDF results also indicate the significance of the inflow and outflow conditions.

1 aYaldizli, M.1 aLi, Z.1 aJaberi, J.A. uhttps://icer.msu.edu/new-model-large-eddy-simulations-multi-phase-turbulent-combustion01659nas a2200145 4500008004100000020001800041245007700059210006900136260003700205520113400242100001101376700001701387700001701404856009201421 2007 eng d a0-7918-4803-500aNumerical Simulations of Two-Phase Turbulent Combustion in Spray Burners0 aNumerical Simulations of TwoPhase Turbulent Combustion in Spray aLas Vegas, NevadabASMEc09/20073 aThe complex interactions among turbulence, combustion and spray in liquid-fuel burners are modeled and simulated via a new two-phase Lagrangian-Eulerian-Lagrangian large eddy simulation (LES) methodology. In this methodology, the spray is modeled with a Lagrangian mathematical/computational method which allows two-way mass, momentum and energy coupling between phases. The subgrid gas-liquid combustion is based on the two-phase filtered mass density function (FMDF) that has several advantages over “conventional” two-phase combustion models. The LES/FMDF is employed in conjunction with non-equilibrium reaction and droplet models. Simulations of turbulent combustion in a spray-controlled double-swirl burner are conducted via LES/FMDF. The generated results are used for better understanding of spray combustion in realistic turbulent flow configurations. The effects of spray angle, mass loading ratio, fuel type, droplet size distribution, wall and inflow/outflow conditions on the flow and combustion are investigated. The LES/FMDF predictions are shown to be consistent with the experimental results.

1 aLi, Z.1 aYaldizli, M.1 aJaberi, F.A. uhttps://icer.msu.edu/numerical-simulations-two-phase-turbulent-combustion-spray-burners