Bio


Large-eddy simulation and modeling of turbulent reacting flows, non-premixed flame, aeroacoustics and combustion generated noise, turbulence and fluid dynamics, numerical methods and high-order schemes.

Academic Appointments


Professional Education


  • Ph.D, Stanford University, Mechanical Engineering (2008)
  • M.Sc., University of Erlangen, Germany, Computational Engineering (2002)
  • Dipl.-Ing., Munich University of Applied Sciences, Germany, Mechanical Engineering (2000)

2017-18 Courses


Stanford Advisees


All Publications


  • Nonadiabatic Flamelet Formulation for Predicting Wall Heat Transfer in Rocket Engines AIAA JOURNAL Ma, P. C., Wu, H., Ihme, M., Hickey, J. 2018; 56 (6): 2336–49

    View details for DOI 10.2514/1.J056539

    View details for Web of Science ID 000433557100022

  • Structure of wall-bounded flows at transcritical conditions PHYSICAL REVIEW FLUIDS Ma, P. C., Yang, X. A., Ihme, M. 2018; 3 (3)
  • Effects of Nozzle Helmholtz Number on Indirect Combustion Noise by Compositional Perturbations JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME Magri, L., O'Brien, J., Ihme, M. 2018; 140 (3)

    View details for DOI 10.1115/1.4037914

    View details for Web of Science ID 000426056900001

  • Phase transitions of ordered ice in graphene nanocapillaries and carbon nanotubes SCIENTIFIC REPORTS Raju, M., van Duin, A., Ihme, M. 2018; 8: 3851

    Abstract

    New phase diagrams for water confined in graphene nanocapillaries and single-walled carbon nanotubes (CNTs) are proposed, identifying ice structures, their melting points and revealing the presence of a solid-liquid critical point. For quasi-2D water in nanocapillaries, we show through molecular-dynamics simulations that AA stacking in multilayer quasi-2D ice arises from interlayer hydrogen-bonding and is stable up to three layers, thereby explaining recent experimental observations. Detailed structural and energetic analyses show that quasi-2D water can freeze discontinuously through a first-order phase transition or continuously with a critical point. The first-order transition line extends to a continuous transition line, defined by a sharp transition in diffusivity between solid-like and liquid-like regimes. For quasi-1D water, confined in CNTs, we observe the existence of a similar critical point at intermediate densities. In addition, an end point is identified on the continuous-transition line, above which the solid and liquid phases deform continuously. The solid-liquid phase transition temperatures in CNTs are shown to be substantially higher than 273 K, confirming recent Raman spectroscopy measurements. We observe ultrafast proton and hydroxyl transport in quasi-1D and -2D ice at 300 K, exceeding those of bulk water up to a factor of five, thereby providing possible applications to fuel-cells and electrolyzers.

    View details for DOI 10.1038/s41598-018-22201-3

    View details for Web of Science ID 000426354200023

    View details for PubMedID 29497132

    View details for PubMedCentralID PMC5832794

  • Atomistic and continuum scale modeling of functionalized graphyne membranes for water desalination NANOSCALE Raju, M., Govindaraju, P. B., van Duin, A. T., Ihme, M. 2018; 10 (8): 3969–80

    Abstract

    Recent theoretical and experimental studies reported ultra-high water permeability and salt rejection in nanoporous single-layer graphene. However, creating and controlling the size and distribution of nanometer-scale pores pose significant challenges to application of these membranes for water desalination. Graphyne and hydrogenated graphyne have tremendous potential as ultra-permeable membranes for desalination and wastewater reclamation due to their uniform pore-distribution, atomic thickness and mechano-chemical stability. Using molecular dynamics (MD) simulations and upscale continuum analysis, the desalination performance of bare and hydrogenated α-graphyne and γ-{2,3,4}-graphyne membranes is evaluated as a function of pore size, pore geometry, chemical functionalization and applied pressure. MD simulations show that pores ranging from 20 to 50 Å2 reject in excess of 90% of the ions for pressures up to 1 GPa. Water permeability is found to range up to 85 L cm-2 day-1 MPa-1, which is up to three orders of magnitude larger than commercial seawater reverse osmosis (RO) membranes and up to ten times that of nanoporous graphene. Pore chemistry, functionalization and geometry are shown to play a critical role in modulating the water flux, and these observations are explained by water velocity, density, and energy barriers in the pores. The atomistic scale investigations are complemented by upscale continuum analysis to examine the performance of these membranes in application to cross-flow RO systems. This upscale analysis, however, shows that the significant increase in permeability, observed from MD simulations, does not fully translate to current RO systems due to transport limitations. Nevertheless, upscale calculations predict that the higher permeability of graphyne membranes would allow up to six times higher permeate recovery or up to 6% less energy consumption as compared to thin-film composite membranes at currently accessible operating conditions. Significantly higher energy savings and permeate recovery can be achieved if higher feed-flow rates can be realized.

    View details for DOI 10.1039/c7nr07963j

    View details for Web of Science ID 000426148500045

    View details for PubMedID 29424378

  • Formulation of optimal surrogate descriptions of fuels considering sensitivities to experimental uncertainties COMBUSTION AND FLAME Govindaraju, P. B., Ihme, M. 2018; 188: 337–56
  • On underresolved simulations of compressible turbulence using an entropy-bounded DG method: Solution stabilization, scheme optimization, and benchmark against a finite-volume solver COMPUTERS & FLUIDS Lv, Y., Ma, P. C., Ihme, M. 2018; 161: 89–106
  • Flamelet regime characterization for non-premixed turbulent combustion simulations COMBUSTION AND FLAME Chan, W., Ihme, M. 2017; 186: 220–35
  • A general probabilistic approach for the quantitative assessment of LES combustion models COMBUSTION AND FLAME Johnson, R., Wu, H., Ihme, M. 2017; 183: 88–101
  • Similarity law for Widom lines and coexistence lines PHYSICAL REVIEW E Banuti, D. T., Raju, M., Ihme, M. 2017; 95 (5)
  • Non-equilibrium wall-modeling for internal combustion engine simulations with wall heat transfer INTERNATIONAL JOURNAL OF ENGINE RESEARCH Ma, P. C., Greene, M., Sick, V., Ihme, M. 2017; 18 (1-2): 15-25
  • Regularized deconvolution method for turbulent combustion modeling COMBUSTION AND FLAME Wang, Q., Ihme, M. 2017; 176: 125-142
  • Development and Analysis of Wall Models for Internal Combustion Engine Simulations Using High-speed Micro-PIV Measurements FLOW TURBULENCE AND COMBUSTION Ma, P. C., Ewan, T., Jainski, C., Lu, L., Dreizler, A., Sick, V., Ihme, M. 2017; 98 (1): 283-309
  • Combustion and Engine-Core Noise ANNUAL REVIEW OF FLUID MECHANICS, VOL 49 Ihme, M. 2017; 49: 277-310
  • Regimes describing shock boundary layer interaction and ignition in shock tubes PROCEEDINGS OF THE COMBUSTION INSTITUTE Grogan, K. P., Ihme, M. 2017; 36 (2): 2927-2935
  • Numerical investigation of soot-flame-vortex interaction PROCEEDINGS OF THE COMBUSTION INSTITUTE Franzelli, B., Cuoci, A., Stagni, A., Ihme, M., Faravelli, T., Candel, S. 2017; 36 (1): 753-761
  • The role of preferential evaporation on the ignition of multicomponent fuels in a homogeneous spray/air mixture PROCEEDINGS OF THE COMBUSTION INSTITUTE Stagni, A., Esclapez, L., Govindaraju, P., Cuoci, A., Faravelli, T., Ihme, M. 2017; 36 (2): 2483-2491
  • The cross-scale physical-space transfer of kinetic energy in turbulent premixed flames PROCEEDINGS OF THE COMBUSTION INSTITUTE O'Brien, J., Towery, C. A., Hamlington, P. E., Ihme, M., Poludnenko, A. Y., Urzay, J. 2017; 36 (2): 1967-1975
  • Classification and lift-off height prediction of non-premixed MILD and autoignitive flames PROCEEDINGS OF THE COMBUSTION INSTITUTE Evans, M. J., Medwell, P. R., Wu, H., Stagni, A., Ihme, M. 2017; 36 (3): 4297-4304
  • Multiple-scale thermo-acoustic stability analysis of a coaxial jet combustor PROCEEDINGS OF THE COMBUSTION INSTITUTE Magri, L., See, Y., Tammisola, O., Ihme, M., Juniper, M. P. 2017; 36 (3): 3863-3871
  • An investigation of internal flame structure in porous media combustion via X-ray Computed Tomography PROCEEDINGS OF THE COMBUSTION INSTITUTE Dunnmon, J., Sobhani, S., Wu, M., Fahrig, R., Ihme, M. 2017; 36 (3): 4399-4408
  • Compliance of combustion models for turbulent reacting flow simulations FUEL Wu, H., Ihme, M. 2016; 186: 853-863
  • Group contribution method for multicomponent evaporation with application to transportation fuels INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER Govindaraju, P. B., Ihme, M. 2016; 102: 833-845
  • An entropy-residual shock detector for solving conservation laws using high-order discontinuous Galerkin methods JOURNAL OF COMPUTATIONAL PHYSICS Lv, Y., See, Y. C., Ihme, M. 2016; 322: 448-472
  • Compositional inhomogeneities as a source of indirect combustion noise JOURNAL OF FLUID MECHANICS Magri, L., O'Brien, J., Ihme, M. 2016; 799
  • Spectral kinetic energy transfer in turbulent premixed reacting flows PHYSICAL REVIEW E Towery, C. A., Poludnenko, A. Y., Urzay, J., O'Brien, J., Ihme, M., Hamlington, P. E. 2016; 93 (5)

    Abstract

    Spectral kinetic energy transfer by advective processes in turbulent premixed reacting flows is examined using data from a direct numerical simulation of a statistically planar turbulent premixed flame. Two-dimensional turbulence kinetic-energy spectra conditioned on the planar-averaged reactant mass fraction are computed through the flame brush and variations in the spectra are connected to terms in the spectral kinetic energy transport equation. Conditional kinetic energy spectra show that turbulent small-scale motions are suppressed in the burnt combustion products, while the energy content of the mean flow increases. An analysis of spectral kinetic energy transfer further indicates that, contrary to the net down-scale transfer of energy found in the unburnt reactants, advective processes transfer energy from small to large scales in the flame brush close to the products. Triadic interactions calculated through the flame brush show that this net up-scale transfer of energy occurs primarily at spatial scales near the laminar flame thermal width. The present results thus indicate that advective processes in premixed reacting flows contribute to energy backscatter near the scale of the flame.

    View details for DOI 10.1103/PhysRevE.93.053115

    View details for Web of Science ID 000376644900015

    View details for PubMedID 27300986

  • Characterizing spray flame-vortex interaction: A spray spectral diagram for extinction COMBUSTION AND FLAME Franzelli, B., Vie, A., Ihme, M. 2016; 163: 100-114
  • On the generalisation of the mixture fraction to a monotonic mixing-describing variable for the flamelet formulation of spray flames COMBUSTION THEORY AND MODELLING Franzelli, B., Vie, A., Ihme, M. 2015; 19 (6): 773-806
  • A Pareto-efficient combustion framework with submodel assignment for predicting complex flame configurations COMBUSTION AND FLAME Wu, H., See, Y. C., Wang, Q., Ihme, M. 2015; 162 (11): 4208-4230
  • Characterization of scalar mixing in dense gaseous jets using X-ray computed tomography EXPERIMENTS IN FLUIDS Dunnmon, J., Sobhani, S., Kim, T. W., Kovscek, A., Ihme, M. 2015; 56 (10)
  • Entropy-bounded discontinuous Galerkin scheme for Euler equations JOURNAL OF COMPUTATIONAL PHYSICS Lv, Y., Ihme, M. 2015; 295: 715-739
  • Ignition regimes in rapid compression machines COMBUSTION AND FLAME Grogan, K. P., Goldsborough, S. S., Ihme, M. 2015; 162 (8): 3071-3080
  • An SMLD Joint PDF Model for Turbulent Non-Premixed Combustion Using the Flamelet Progress-Variable Approach FLOW TURBULENCE AND COMBUSTION Coclite, A., Pascazio, G., De Palma, P., Cutrone, L., Ihme, M. 2015; 95 (1): 97-119
  • Quantitative model-based imaging of mid-infrared radiation from a turbulent nonpremixed jet flame and plume COMBUSTION AND FLAME Rankin, B. A., Ihme, M., Gore, J. P. 2015; 162 (4): 1275-1283
  • A multi-scale asymptotic scaling and regime analysis of flamelet equations including tangential diffusion effects for laminar and turbulent flames COMBUSTION AND FLAME Scholtissek, A., Chan, W. L., Xu, H., Hunger, F., Kolla, H., Chen, J. H., Ihme, M., Hasse, C. 2015; 162 (4): 1507-1529
  • Weak and strong ignition of hydrogen/oxygen mixtures in shock-tube systems PROCEEDINGS OF THE COMBUSTION INSTITUTE Grogan, K. P., Ihme, M. 2015; 35: 2181-2189
  • Large eddy simulation of a partially-premixed gas turbine model combustor PROCEEDINGS OF THE COMBUSTION INSTITUTE See, Y. C., Ihme, M. 2015; 35: 1225-1234
  • Analysis of segregation and bifurcation in turbulent spray flames: A 3D counterflow configuration PROCEEDINGS OF THE COMBUSTION INSTITUTE Vie, A., Franzelli, B., Gao, Y., Lu, T., Wang, H., Ihme, M. 2015; 35: 1675-1683
  • Computational analysis of re-ignition and re-initiation mechanisms of quenched detonation waves behind a backward facing step PROCEEDINGS OF THE COMBUSTION INSTITUTE Lv, Y., Ihme, M. 2015; 35: 1963-1972
  • Coupling of flame geometry and combustion instabilities based on kilohertz formaldehyde PLIF measurements PROCEEDINGS OF THE COMBUSTION INSTITUTE Allison, P. M., Chen, Y., Ihme, M., Driscoll, J. F. 2015; 35: 3255-3262
  • Instability of elliptic liquid jets: Temporal linear stability theory and experimental analysis PHYSICS OF FLUIDS Amini, G., Lv, Y., Dolatabadi, A., Ihme, M. 2014; 26 (11)

    View details for DOI 10.1063/1.4901246

    View details for Web of Science ID 000345578700024

  • Assessment of model assumptions and budget terms of the unsteady flamelet equations for a turbulent reacting jet-in-cross-flow COMBUSTION AND FLAME Chan, W. L., Kolla, H., Chen, J. H., Ihme, M. 2014; 161 (10): 2601-2613
  • Effects of flow-field and mixture inhomogeneities on the ignition dynamics in continuous flow reactors COMBUSTION AND FLAME Wu, H., Ihme, M. 2014; 161 (9): 2317-2326
  • Tabulated chemistry approach for diluted combustion regimes with internal recirculation and heat losses COMBUSTION AND FLAME Lamouroux, J., Ihme, M., Fiorina, B., Gicquel, O. 2014; 161 (8): 2120-2136
  • Discontinuous Galerkin method for multicomponent chemically reacting flows and combustion JOURNAL OF COMPUTATIONAL PHYSICS Lv, Y., Ihme, M. 2014; 270: 105-137
  • Modeling of Non-Equilibrium Homogeneous Turbulence in Rapidly Compressed Flows FLOW TURBULENCE AND COMBUSTION Hamlington, P. E., Ihme, M. 2014; 93 (1): 93-124
  • Effects of finite-rate chemistry and detailed transport on the instability of jet diffusion flames JOURNAL OF FLUID MECHANICS See, Y. C., Ihme, M. 2014; 745: 647-681
  • Subgrid-scale backscatter in reacting and inert supersonic hydrogen-air turbulent mixing layers JOURNAL OF FLUID MECHANICS O'Brien, J., Urzay, J., Ihme, M., Moin, P., Saghafian, A. 2014; 743: 554-584
  • Large-eddy simulation of a piloted premixed jet burner COMBUSTION AND FLAME Chen, Y., Ihme, M. 2013; 160 (12): 2896-2910
  • Effect of gravity on capillary instability of liquid jets PHYSICAL REVIEW E Amini, G., Ihme, M., Dolatabadi, A. 2013; 87 (5)

    Abstract

    The effect of gravity on the onset and growth rate of capillary instabilities in viscous liquid jets is studied. To this end, a spatial linear stability analysis of Cosserat's equations is performed using a multiscale expansion technique. A dispersion relation and expressions for the perturbation amplitude are derived to evaluate the growth rate of the most unstable axisymmetric disturbance mode. Modeling results are compared with classical results in the limit of zero Bond number, confirming the validity of this approach. Expressions for the critical Weber number, demarcating the transition between convective and absolute instability are derived as functions of capillary and Bond numbers. Parametric investigations for a range of relevant operating conditions (characterized by capillary, Weber, and Bond numbers) are performed to examine the jet breakup and the perturbation growth rate. In addition to the physical insight that is obtained from this investigation, the results that are presented in this work could also be of relevance as test cases for the algorithmic development and the verification of high-fidelity multiphase simulation codes.

    View details for DOI 10.1103/PhysRevE.87.053017

    View details for Web of Science ID 000319284800009

    View details for PubMedID 23767630

  • Effect of gravity on capillary instability of liquid jets. Physical Review E Amini, G., Ihme, M., Dolatabadi, A. 2013; 87: 053017
  • Acoustic characterization of a partially-premixed gas turbine model combustor: Syngas and hydrocarbon fuel comparisons PROCEEDINGS OF THE COMBUSTION INSTITUTE Allison, P. M., Driscoll, J. F., Ihme, M. 2013; 34: 3145-3153
  • Liquid Jet Instability Under Gravity Effects. Amini, G., Ihme, M. 2013
  • Detailed Simulations of Shock-Bifurcation and Ignition of an Argon-diluted Hydrogen/Oxygen Mixture in a Shock Tube. Ihme, M., Sun, Y., Deterding, R. 2013
  • Large Eddy Simulation of Shear Coaxial Rocket Injector: Real Fluid Effects. Hickey, J., P., Ma, P., C., Ihme, M., Thakur, S. 2013
  • Discontinuous Galerkin Method for Compressible Viscous Reacting Flows. Lv, Y., Ihme, M. 2013
  • Acoustic characterization of a partially-premixed gas turbine model combustor: Syngas and hydrocarbon fuel comparisons. Allison, P., M., Driscoll, J., F., Ihme, M. 2013
  • Regularization of reaction progress variable for application to flamelet-based combustion models. Journal of Computational Physics Ihme, M., Shunn, L., Zhang, J. 2012; 23 (231): 7715-7721
  • On the generation of direct combustion noise in turbulent non-premixed flames INTERNATIONAL JOURNAL OF AEROACOUSTICS Ihme, M., Pitsch, H. 2012; 11 (1): 25-78
  • On the generation of direct combustion noise in turbulent nonpremixed flames. International Journal of Aeroacoustics Ihme, M., Pitsch, H. 2012; 11: 25-78
  • On the role of turbulence in rapid compression machines: Autoignition of syngas mixtures. Combustion and Flame Ihme, M. 2012; 157: 1592-1604
  • Large-eddy simulation of a jet in hot coflow burner operating in the oxygen-diluted combustion regime. Flow, Turbulence and Combustion Ihme, M., Zhang, J., He, G., Dally, B. 2012; 3 (89): 449-464
  • Reduced order modeling of turbulent reacting flows with application to scramjets. Journal of Propulsion and Power Torrez, S., M., Driscoll, J., F., Ihme, M., Fotia, M., L. 2011; 2 (27): 371-382
  • LES Modeling of a Turbulent Lifted Flame in a Vitiated Co-flow Using an Unsteady Flamelet/Progress Variable Formulation 8th Workshop on Direct and Large-Eddy Simulation Ihme, M., See, Y. C. SPRINGER. 2011: 339–344
  • LES flamelet modeling of a three-stream MILD combustor: Analysis of flame sensitivity to scalar inflow conditions PROCEEDINGS OF THE COMBUSTION INSTITUTE Ihme, M., See, Y. C. 2011; 33: 1309-1317
  • LES modeling of a turbulent lifted flame in a vitiated co-flow using an unsteady flamelet/progress variable formulation. Direct and Large-Eddy Simulation VIII, Proceedings of the Eighth International ERCOFTAC Workshop on Direct and Large-Eddy Simulation Ihme, M., See, Y., C. edited by Kuerten, J., G.M. University of Eindhoven. 2011
  • LES modeling of a turbulent lifted flame in a vitiated co-flow using an unsteady flamelet/progress variable formulation. M., Ihme, Y., See, C. edited by Kuerten, J., G.M. 2011
  • Characterization of flow field structure and species composition in a shear coaxial rocket GH2/GO2 injector: Modeling of wall heat losses. Presented at the 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, AIAA 2011-6125, San Diego, CA Lee, D., J., Thakur, S., Wright, J., Ihme, M., Shyy, W. 2011
  • Characterization of flow field structure and species composition in a shear coaxial rocket GH2/GO2 injector: Modeling of wall heat losses. Lee, D., J., Thakur, S., Wright, J., Ihme, M., Shyy, W. 2011
  • LES of a gaseous H2/O2 rocket injector: Wall heat transfer modeling. Lee, D., J., Ihme, M., Thakur, S., Shyy, W. 2011
  • Reconcile discrepancies of current syngas kinetics models by considering turbulence effects on ignition delay at gas-turbine relevant operating conditions. Ihme, M. 2011
  • LES flamelet modeling of a three-stream MILD combustor: Analysis of flame sensitivity to scalar inflow conditions. Ihme, M., See, Y., C. 2011
  • Construction of Optimal Artificial Neural Network Architectures for Application to Chemical Systems: Comparison of Generalized Pattern Search Method and Evolutionary Algorithm. Artificial Neural Networks Ihme, M. InTech Open Access Publisher. 2011
  • Prediction of autoignition in a lifted methane/air flame using an unsteady flamelet/progress variable model COMBUSTION AND FLAME Ihme, M., See, Y. C. 2010; 157 (10): 1850-1862
  • Prediction of autoignition in a lifted methane/air flame using an unsteady flamelet/progress variable model. Combustion and Flame Ihme, M., See, Y., C. 2010; 157: 1850-1862
  • Topological Optimization of Artificial Neural Networks Using a Pattern Search Method. Neural Computation and Particle Accelerators: Research, Technology and Applications (Neuroscience Research Progress) Ihme, M. edited by Chabot, E., D’arras, H. Nova Science Publishers. 2010
  • Analysis of different sound source formulations to simulate combustion generated noise using a hybrid LES/APE-RF method. International Journal of Aeroacoustics Bui, T., P., Ihme, M., Schroeder, W., Pitsch, H. 2009; 1-2 (8): 95-123
  • Optimal artificial neural networks and tabulation methods for chemistry representation in LES of a bluff-body swirl-stabilized flame PROCEEDINGS OF THE COMBUSTION INSTITUTE Ihme, M., Schmitt, C., Pitsch, H. 2009; 32: 1527-1535
  • Radiation of noise in turbulent non-premixed flames PROCEEDINGS OF THE COMBUSTION INSTITUTE Ihme, M., Pitsch, H., Bodony, D. 2009; 32: 1545-1553
  • Prediction of extinction and reignition in nonpremixed turbulent flames using a flamelet/progress variable model 1. A priori study and presumed PDF closure COMBUSTION AND FLAME Ihme, M., Pitsch, H. 2008; 155 (1-2): 70-89
  • Prediction of extinction and reignition in nonpremixed turbulent flames using a flamelet/progress variable model 2. Application in LES of Sandia flames D and E COMBUSTION AND FLAME Ihme, M., Pitsch, H. 2008; 155 (1-2): 90-107
  • Modeling of radiation and nitric oxide formation in turbulent nonpremixed flames using a flamelet/progress variable formulation PHYSICS OF FLUIDS Ihme, M., Pitsch, H. 2008; 20 (5)

    View details for DOI 10.1063/1.2911047

    View details for Web of Science ID 000256304800032

  • Generation of optimal artificial neural networks using a pattern search algorithm: Application to approximation of chemical systems NEURAL COMPUTATION Ihme, M., Marsden, A. L., Pitsch, H. 2008; 20 (2): 573-601

    Abstract

    A pattern search optimization method is applied to the generation of optimal artificial neural networks (ANNs). Optimization is performed using a mixed variable extension to the generalized pattern search method. This method offers the advantage that categorical variables, such as neural transfer functions and nodal connectivities, can be used as parameters in optimization. When used together with a surrogate, the resulting algorithm is highly efficient for expensive objective functions. Results demonstrate the effectiveness of this method in optimizing an ANN for the number of neurons, the type of transfer function, and the connectivity among neurons. The optimization method is applied to a chemistry approximation of practical relevance. In this application, temperature and a chemical source term are approximated as functions of two independent parameters using optimal ANNs. Comparison of the performance of optimal ANNs with conventional tabulation methods demonstrates equivalent accuracy by considerable savings in memory storage. The architecture of the optimal ANN for the approximation of the chemical source term consists of a fully connected feedforward network having four nonlinear hidden layers and 117 synaptic weights. An equivalent representation of the chemical source term using tabulation techniques would require a 500 x 500 grid point discretization of the parameter space.

    View details for Web of Science ID 000252248200012

    View details for PubMedID 18045024

  • Prediction of extinction and reignition in non-premixed turbulent flames using a flamelet/progress variable model 2. Application in LES of Sandia Flames D and E. Combustion and Flame Ihme, M., Pitsch, H. 2008; 155: 90-107
  • Modeling of radiation and nitric oxide formation in turbulent nonpremixed flames using a flamelet/progress variable formulation. Physics of Fluids Ihme, M., Pitsch, H. 2008; 20: 055110
  • Construction of optimal artificial neural networks for tabulated chemistry using a pattern search algorithm. Ihme, M., Pitsch, H. 2008
  • Large-eddy simulation of turbulent reacting flows. Progress in Aerospace Sciences Pitsch, H., Desjardins, O., Balarac, G., Ihme, M. 2008; 6 (44): 466-478
  • Prediction of extinction and reignition in non-premixed turbulent flames using a flamelet/progress variable model 1. A priori study and presumed PDF closure. Combustion and Flame Ihme, M., Pitsch, H. 2008; 155: 70-89
  • Generation of optimal artificial neural networks using a pattern search algorithm: Application to approximation of chemical systems. Neural Computation Ihme, M., Marsden, A., L., Pitsch, H. 2008; 20: 573–601
  • On the optimization of artificial neural networks for application to the approximation of chemical systems. Center for Turbulence Research Annual Research Briefs Ihme, M., Marsden, A., L., Pitsch, H. 2006: 105–118
  • Towards the prediction of combustion-generated noise in non-premixed turbulent flames using large-eddy simulation. Center for Turbulence Research Annual Research Briefs Ihme, M., Bodony, D., Pitsch, H. 2005: 311–323
  • Prediction of local extinction and re-ignition effects in non-premixed turbulent combustion using a flamelet/progress variable approach 30th International Symposium on Combustion Ihme, M., Cha, C. M., Pitsch, H. ELSEVIER SCIENCE INC. 2005: 793–800
  • Stochastic mixing model with power law decay of variance PHYSICAL REVIEW E Fedotov, S., Ihme, M., Pitsch, H. 2005; 71 (1)

    Abstract

    A stochastic mixing model based on the law of large numbers is presented that describes the decay of the variance of a conserved scalar in decaying turbulence as a power law, sigma2(c) proportional t(-alpha). A general Lagrangian mixing process is modeled by a stochastic difference equation where the mixing frequency and the ambient concentration are random processes. The mixing parameter lambda is introduced as a coefficient in the mixing frequency in order to account for initial length-scale ratio of the velocity and scalar field and other physical dependencies. We derive a nonlinear integral equation for the probability density function (pdf) of a conserved scalar that describes the relaxation of an arbitrary initial distribution to a delta-function. Numerical studies of this equation are conducted, and it is shown that lambda has a distinct influence on the decay rate of the scalar. Results obtained from the model for the evolution of the pdf are in a good agreement with direct numerical simulation (DNS) data.

    View details for DOI 10.1103/PhysRevE.71.016310

    View details for Web of Science ID 000227459400087

    View details for PubMedID 15697725

  • Stochastic mixing model with power law decay of variance. Physical Review E Fedotov, S., Ihme, M., Pitsch, H. 2005; 1 (71): 1–9
  • Numerical prediction of nitrogen oxide emission using flamelet/progress variable model. Ihme, M., Pitsch, H. 2005
  • LES of a non-premixed flame using an extended flamelet/progress variable model. Ihme, M., Pitsch, H. 2005
  • Flamelet/progress variable model closure with statistically mostlikely distribution. Ihme, M., Pitsch, H. 2005
  • An unsteady/flamelet progress variable method for LES of nonpremixed turbulent combustion. Pitsch, H., Ihme, M. 2005
  • Prediction of local extinction and re-ignition effects in non-premixed turbulent combustion using a flamelet/progress variable approach. Ihme, M., Cha, C., M., Pitsch, H. 2005
  • An extended flamelet/progress variable method for LES of nonpremixed turbulent combustion. Ihme, M., Pitsch, H. 2004
  • Stochastic mixing model with power law decay of variance. Center for Turbulence Research Annual Research Briefs Fedotov, S., Ihme, M., Pitsch, H. 2003: 285–296