@inproceedings{MovagharLinneOevermannetal., author = {Movaghar, Amirreza and Linne, Mark and Oevermann, Michael and Meiselbach, Falko T. and Schmidt, Heiko and Kerstein, Alan R.}, title = {Numerical study of liquid breakup at the surface of turbulent liquid jets using One-Dimensional Turbulence}, series = {26th Annual Conference on Liquid Atomization and Spray Systems, ILASS, proceedings of the Conference, Bremen, Germany, 08.09.2014 - 10.09.2014}, booktitle = {26th Annual Conference on Liquid Atomization and Spray Systems, ILASS, proceedings of the Conference, Bremen, Germany, 08.09.2014 - 10.09.2014}, address = {Bremen}, isbn = {978-3-00-047070-7}, abstract = {This paper presents an investigation of primary breakup of planar turbulent liquid jets and breakup properties at the surface of turbulent jets in still air at standard conditions. Numerical simulations are carried out for jet exit Reynolds number 23000 and Weber numbers in the range [102-107]. Due to the limitation of direct numerical simulation (DNS) to moderate Reynolds numbers, a stochastic 1D ansatz based on the one-dimensional turbulence (ODT) model is used to simulate a planar liquid jet with a high lateral resolution. ODT permits an affordable high resolution of interface and single-phase property gradients which are key for understanding the local behavior. ODT is a stochastic model simulating turbulent flow evolution along a notional 1D line of sight by applying instantaneous maps to represent the effect of individual turbulent eddies on property profiles. The most relevant mechanisms that influence the primary breakup of liquid jets are found to be represented accurately based on comparisons to experiments and correlations reported in the literature. Building on this finding, future work will focus on the statistics of droplets generated by primary breakup, both to investigate their relationship to breakup mechanisms and to provide input to models of secondary breakup and subsequent spray evolution.}, 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} } @inproceedings{SarradjMeiselbach, author = {Sarradj, Ennes and Meiselbach, Falko T.}, title = {Berechnung von Schalld{\"a}mpfern mit Platten- oder Membran-Auskleidung}, series = {Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. M{\"a}rz 2016, 42. Jahrestagung f{\"u}r Akustik}, booktitle = {Fortschritte der Akustik, DAGA 2016, Aachen, 14.-17. M{\"a}rz 2016, 42. Jahrestagung f{\"u}r Akustik}, publisher = {DAGA}, address = {Berlin}, isbn = {978-3-939296-10-2}, language = {de} } @misc{MovagharLinneOevermannetal., author = {Movaghar, Amirreza and Linne, Mark and Oevermann, Michael and Meiselbach, Falko T. and Schmidt, Heiko and Kerstein, Alan R.}, title = {Numerical investigation of turbulent-jet primary breakup using One-Dimensional Turbulence}, series = {International Journal of Multiphase Flow}, volume = {89}, journal = {International Journal of Multiphase Flow}, issn = {1879-3533}, pages = {241 -- 254}, abstract = {Primary breakup to form droplets at liquid surfaces is an important fundamental process to study as it determines the initial properties of the dispersed phase, which affect mixing rates, secondary breakup, droplet collisions, and flow separation within the dispersed flow region. Primary breakup can be regarded as one of the least developed model components for simulating and predicting liquid jet breakup. How- ever, it is of paramount importance in many technical applications, e.g. fuel injection in engines and spray painting. This paper presents a numerical investigation of primary breakup of a turbulent liquid jet in still air at standard conditions using the one-dimensional turbulence (ODT) modeling framework. ODT is a stochastic model that simulates turbulent flow evolution along a notional 1D line of sight by applying instantaneous maps to represent the effect of individual turbulent eddies on property profiles. An important feature of ODT is the resolution of all relevant scales, both temporal and spatial. The restriction to one spatial dimension in ODT permits affordable high resolution of interfacial and single-phase property gradients, which is key to capturing the local behavior of the breakup process and allows simulations at high Reynolds and Weber numbers that are currently not accessible to direct numerical simulations (DNS). This paper summarizes our extensions of the ODT model to simulate geometrically simple jet breakup problems, including representations of Rayleigh wave breakup, turbulent breakup, and shear-driven breakup. Each jet breakup simulation consists of a short temporal channel section to initialize a turbulent velocity profile at the nozzle exit followed by an adjacent jet section. The simulations are carried out for jet exit Reynolds number of 11,500, 23,000, 46,000 and 92,000 while the Weber number is varied within the range 102-107. We present results on breakup statistics including spatial locations of droplet release, droplet sizes and liquid core length. The results on primary breakup are compared to experimental results and models.}, language = {en} } @phdthesis{Meiselbach, author = {Meiselbach, Falko T.}, title = {Application of ODT to turbulent flow problems}, url = {http://nbn-resolving.de/nbn:de:kobv:co1-opus4-34952}, pages = {181}, language = {en} }