@misc{JozefikKersteinSchmidtetal., author = {Jozefik, Zoltan and Kerstein, Alan R. and Schmidt, Heiko and Lyra, Sgouria and Kolla, Hemanth and Chen, Jackie H.}, title = {One-dimensional turbulence modeling of a turbulent counterflow flame with comparison to DNS}, series = {Combustion and Flame}, volume = {162}, journal = {Combustion and Flame}, number = {8}, issn = {1556-2921}, pages = {2999 -- 3015}, language = {en} } @misc{SchmidtGlaweJozefiketal., author = {Schmidt, Heiko and Glawe, Christoph and Jozefik, Zoltan and Meiselbach, Falko T. and Kerstein, Alan R.}, title = {On the benefits of ODT-based stochastic turbulence modeling}, series = {Proceedings in applied mathematics and mechanics : PAMM}, volume = {14}, journal = {Proceedings in applied mathematics and mechanics : PAMM}, number = {1}, issn = {1617-7061}, pages = {655 -- 656}, abstract = {We summarize the group's progress in applying, analyzing, and improving ODT and ODT-based stochastic turbulence models like ODTLES. Compared to DNS these models span a wider range of scales while compared to RANS/LES (i) the molecular effects are retained and (ii) no assumption of scale separation is made. In this regard ODTLES has more properties of DNS than of standard LES.}, language = {en} } @misc{JozefikKersteinSchmidtetal., author = {Jozefik, Zoltan and Kerstein, Alan R. and Schmidt, Heiko and Lyra, Sgouria and Kolla, Hemanth and Chen, Jackie H.}, title = {One-dimensional turbulence modeling of a turbulent counterflow flame with comparison to DNS}, series = {Combustion and Flame}, volume = {162}, journal = {Combustion and Flame}, number = {8}, issn = {0010-2180}, doi = {10.1016/j.combustflame.2015.05.010}, pages = {2999 -- 3015}, abstract = {The one-dimensional turbulence (ODT) model is applied to a reactant-to-product counterflow configuration and results are compared with DNS data. The model employed herein solves conservation equations for momentum, energy, and species on a one dimensional (1D) domain corresponding to the line spanning the domain between nozzle orifice centers. The effects of turbulent mixing are modeled via a stochastic process, while the Kolmogorov and reactive length and time scales are explicitly resolved and a detailed chemical kinetic mechanism is used. Comparisons between model and DNS results for spatial mean and root-mean-square (RMS) velocity, temperature, and major and minor species profiles are shown. The ODT approach shows qualitatively and quantitatively reasonable agreement with the DNS data. Scatter plots and statistics conditioned on temperature are also compared for heat release rate and all species. ODT is able to capture the range of results depicted by DNS. However, conditional statistics show signs of underignition.}, language = {en} } @misc{JozefikKersteinSchmidt, author = {Jozefik, Zoltan and Kerstein, Alan R. and Schmidt, Heiko}, title = {Simulation of shock-turbulence interaction in non-reactive flow and in turbulent deflagration and detonation regimes using one-dimensional turbulence}, series = {Combustion and Flame}, volume = {164}, journal = {Combustion and Flame}, issn = {0010-2180}, doi = {10.1016/j.combustflame.2015.10.035}, pages = {53 -- 67}, abstract = {The one-dimensional turbulence (ODT) methodology is extended to include an efficient compressible implementation and a model for capturing shock-induced turbulence is presented. Lignell et al. recently introduced a Lagrangian ODT implementation using an adaptive mesh. As the code operates in the incompressible regime (apart from constant-pressure dilatation) it cannot handle compressibility effects and their interactions with turbulence and chemistry. The necessary algorithmic changes to include compressibility effects are highlighted and our model for capturing shock- turbulence interaction is presented. To validate our compressible solver, we compare results for the Sod shock tube problem against a finite volume Riemannsolver. To validate our model for shock-turbulence interaction, we present comparisons for a non-reactive and a reactive case. First, results of a shock traveling from light (air) to heavy (SF6) with recheck have been simulated to match mixing width growth data of experiments and turbulent kinetic energy results from LES.Then, for one-step chemistry calibrated to represent an acetylene/airmixture we simulate the interaction of a shock wave with an expanding flame front, and compare results with 2D simulation (2D-sim) data for flame brush formation and ensuing deflagration-to-detonation transitions (DDT). Results for the Sod shock tube comparison show that the shock speed and profile are captured accurately. Results for the non-reactive shock-recheck problem show that interface growth at all simulated Mach numbers is captured accurately and that the turbulent kinetic energy agrees in order of magnitude with LES data. The reactive shock tube results show that the flame brush thickness compares well to 2D-sim data and that the approximate location and timing of the DDT can be captured. The known sensitivity of DDT characteristics to details of individual flow realizations, seen also in ODT, implies that model agreement can be quantified only by comparing flow ensembles, which are presently unavailable other than in an ODT run-to-run sensitivity study that is reported herein.}, language = {en} } @misc{MedinaMendezSchmidtMaussetal., author = {Medina M{\´e}ndez, Juan Ali and Schmidt, Heiko and Mauß, Fabian and Jozefik, Zoltan}, title = {Constant volume n-Heptane autoignition using One-Dimensional Turbulence}, series = {Combustion and Flame}, volume = {190}, journal = {Combustion and Flame}, issn = {0010-2180}, doi = {10.1016/j.combustflame.2017.12.015}, pages = {388 -- 401}, abstract = {Abstract Constant volume premixed lean n-Heptane/air autoignition at high pressure is investigated using the One-Dimensional Turbulence (ODT) model. The configuration consists of a 1D fixed volume domain with a prescribed velocity spectrum and temperature fluctuations superimposed on an initial uniformly elevated scalar field. The sensitivity of the heat release rate and pressure evolution to the initial temperature distribution is studied by imposing different initial temperature fields while holding the mean, RMS and integral length scale of the field constant. Three detailed chemical mechanisms are employed for the prediction of autoignition and heat release rate. To mitigate the high computational cost associated with the calculation of the chemical source terms in the stiff complex mechanisms, an approach based on the Strang-Splitting method is presented. Finally, a …}, language = {en} }