@misc{MedinaMendezSchmidt, author = {Medina M{\´e}ndez, Juan Ali and Schmidt, Heiko}, title = {Towards the evaluation of heat and mass transfer in pipe flows with cocurrent falling films using One-Dimensional Turbulence}, series = {92nd Annual Meeting of the International Association of Applied Mathematics and Mechanics August 15-19, 2022 Aachen, Germany, Book of Abstracts}, journal = {92nd Annual Meeting of the International Association of Applied Mathematics and Mechanics August 15-19, 2022 Aachen, Germany, Book of Abstracts}, publisher = {RWTH Aachen University}, address = {Aachen}, language = {en} } @misc{SharmaMedinaMendezSchmidtetal., author = {Sharma, Dikshant and Medina M{\´e}ndez, Juan Ali and Schmidt, Heiko and Cremer, Tilman}, title = {Seasonal cold storage with borehole heat exchangers: an application study using numerical simulations}, series = {Tagungsband des Jahrestreffens der DECHEMA-Fachgruppen Computational Fluid Dynamics und W{\"a}rme- und Stoff{\"u}bertragung, 6.-8. M{\"a}rz 2023, Frankfurt am Main, Deutschland}, journal = {Tagungsband des Jahrestreffens der DECHEMA-Fachgruppen Computational Fluid Dynamics und W{\"a}rme- und Stoff{\"u}bertragung, 6.-8. M{\"a}rz 2023, Frankfurt am Main, Deutschland}, publisher = {DECHEMA e.V.}, address = {Frankfurt am Main}, pages = {18 -- 19}, language = {en} } @misc{MedinaMendezSchmidtRiebel, author = {Medina M{\´e}ndez, Juan Ali and Schmidt, Heiko and Riebel, Ulrich}, title = {Towards the stochastic modeling of electrostatic precipitators under dusty gas conditions of charged aerosols}, series = {Book of Abstracts zum Jahrestreffen der DECHEMA-Fachgruppen Aerosoltechnik, Gasreinigung, Mehrphasenstr{\"o}mung und Partikelmesstechnik, 28. - 30. M{\"a}rz 2023}, journal = {Book of Abstracts zum Jahrestreffen der DECHEMA-Fachgruppen Aerosoltechnik, Gasreinigung, Mehrphasenstr{\"o}mung und Partikelmesstechnik, 28. - 30. M{\"a}rz 2023}, publisher = {Universit{\"a}t Paderborn}, address = {Paderborn}, pages = {8 -- 9}, language = {en} } @misc{KleinSchoepsMedinaMendezetal., author = {Klein, Marten and Sch{\"o}ps, Mark Simon and Medina M{\´e}ndez, Juan Al{\´i} and Schmidt, Heiko}, title = {Numerical simulation and analysis of transient Ekman boundary layers using a stochastic turbulence model}, series = {EGU General Assembly 2023}, journal = {EGU General Assembly 2023}, publisher = {EGU - European Geophysical Union}, address = {Vienna, Austria}, doi = {10.5194/egusphere-egu23-9116}, language = {en} } @misc{MedinaMendezSharmaSchmidtetal., author = {Medina M{\´e}ndez, Juan Al{\´i} and Sharma, Sparsh and Schmidt, Heiko and Klein, Marten}, title = {Towards the use of a reduced order and stochastic turbulence model for assessment of far-field sound radiation: low Mach number jet flows}, series = {Book of Abstracts of the 93rd Annual Meeting of the International Association of Applied Mathematics and Mechanics}, journal = {Book of Abstracts of the 93rd Annual Meeting of the International Association of Applied Mathematics and Mechanics}, publisher = {GAMM e.V.}, address = {Dresden}, pages = {413 -- 414}, language = {en} } @misc{MedinaMendezFistlerOevermannetal., author = {Medina M{\´e}ndez, Juan Ali and Fistler, Marco and Oevermann, Michael and Schmidt, Heiko and Riebel, Ulrich}, title = {Economical map-based turbulence models: Developments and perspectives for the numerical analysis of electrostatic precipitation}, series = {Book of Abstracts PARTEC International Congress on Particle Technology, September 26-28, 2023, N{\"u}rnberg}, journal = {Book of Abstracts PARTEC International Congress on Particle Technology, September 26-28, 2023, N{\"u}rnberg}, publisher = {VDI Verlag GmbH}, address = {D{\"u}sseldorf}, pages = {634 -- 638}, language = {en} } @misc{MedinaMendezKleinSchmidt, author = {Medina M{\´e}ndez, Juan Ali and Klein, Marten and Schmidt, Heiko}, title = {Investigating dissipative roughness effects on turbulent drag using a stochastic turbulence model}, series = {18th European Turbulence Conference (ETC18), 4-6 September 2023, Valencia}, journal = {18th European Turbulence Conference (ETC18), 4-6 September 2023, Valencia}, address = {Valencia}, pages = {1}, language = {en} } @misc{MedinaMendezSharmaSchmidtetal., author = {Medina M{\´e}ndez, Juan Ali and Sharma, Sparsh and Schmidt, Heiko and Klein, Marten}, title = {Toward the use of a reduced-order and stochastic turbulence model for assessment of far-field sound radiation: Low Mach number jet flows}, series = {Proceedings in Applied Mathematics and Mechanics}, volume = {23}, journal = {Proceedings in Applied Mathematics and Mechanics}, number = {3}, issn = {1617-7061}, doi = {10.1002/pamm.202300186}, pages = {9}, language = {en} } @misc{KleinMedinaMendezSchoepsetal., author = {Klein, Marten and Medina M{\´e}ndez, Juan Al{\´i} and Sch{\"o}ps, Mark Simon and Schmidt, Heiko and Glawe, Christoph}, title = {Towards physics-based nowcasting of the instantaneous wind velocity profile using a stochastic modeling approach}, series = {STAB Jahresbericht 2024 zum 24. DGLR-Fachsymposium der STAB, 13. - 14. November 2024, Regensburg}, journal = {STAB Jahresbericht 2024 zum 24. DGLR-Fachsymposium der STAB, 13. - 14. November 2024, Regensburg}, publisher = {Deutsche Str{\"o}mungsmechanische Arbeitsgemeinschaft, STAB}, address = {Regensburg [et al.]}, pages = {162 -- 163}, abstract = {The primary objective of this contribution is to provide an overview of the regime-spanning forward modeling capabilities offered by the stochastic one-dimensional turbulence model. The focus is on the applicability of the model and its validation for neutral and stable atmospheric boundary layer flows as a prerequisite for future applications to challenging atmospheric conditions.}, language = {en} } @misc{KleinMedinaMendezSchmidt, author = {Klein, Marten and Medina M{\´e}ndez, Juan Al{\´i} and Schmidt, Heiko}, title = {Resolving the electrostatic boundary layer in a turbulent electrohydrodynamic flow with a map-based stochastic modeling approach}, series = {1st European Fluid Dynamics Conference - Daily Scientific Program}, journal = {1st European Fluid Dynamics Conference - Daily Scientific Program}, address = {Aachen}, pages = {1}, abstract = {Electrohydrodynamically (EHD) enhanced wall-bounded turbulent flows are encountered in various technical applications ranging from air-cleaning devices (like precipitators) to electrolyte flows (like redox flow batteries). The multi-physical processes governing the flow properties, however, are not yet very well understood. This is due the inaccessibility to and limitations of measurement equipment and numerical resolution requirements imposed by the electrostatic charge boundary layer that interacts on different time scales with the turbulent boundary layer. Recent advances in measurement techniques allow to resolve the exponential electrostatic charge boundary layer in a charged particle-ladden, weakly turbulent gas flow [1], which is qualitatively compatible with direct numerical simulation (DNS) results for a weakly turbulent flow of an electrolyte [2] at low Reynolds (Re) number. The challenge that remains is the extrapolation to highly turbulent flow conditions. Charged particles are heavy compared with fluid molecules and can be treated as a high Schmidt (Sc) number scalar, which is a burden for DNS. In this contribution, it is demonstrated that this burden can be overcome for the transient boundary layer evolution by utilizing a radically reduced, map-based stochastic one-dimensional turbulence (ODT) model. The model predicts a significant enhancement of the skin friction drag due to turbulence-induced screening layer depletion [3], as summarized in Fig. 1. In the talk, features of the instantaneous and mean velocity and electrostatic boundary layer will be presented. The plausibility of the model prediction is evaluated on a physical basis, encompassing details of the model formulation and the emerging hydrodynamic and electrokinetic properties of the boundary layer. References [1] W. Xu, S. Jantaˇc, T. Matsuyama, and H. Grosshans. arXiv:2306.06970, 2023. (Accepted for publication by Exp. Fluids.) [2] R. Ostilla-M´onico, and A. A. Lee. Faraday Discuss., 199:159-173, 2017. [3] M. Klein, J. A. Medina M´endez, and H. Schmidt. Tech. Mech., 43:111-127, 2023.}, language = {en} } @misc{KleinStarickZenkeretal., author = {Klein, Marten and Starick, Tommy and Zenker, Christian and Medina M{\´e}ndez, Juan Al{\´i} and Schmidt, Heiko}, title = {Reduced order stochastic modeling of turbulent mixing based on conservative baker's maps}, series = {Proceedings of the 14th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements (ETMM-14)}, journal = {Proceedings of the 14th International ERCOFTAC Symposium on Engineering Turbulence Modelling and Measurements (ETMM-14)}, publisher = {ERCOFTAC}, address = {Barcelona, Spain}, pages = {613 -- 618}, abstract = {The detailed numerical representation of turbulent mixing processes is a standing challenge for non-premixed chemically reacting flows. The full range of relevant flow scales needs to be captured and it is also necessary to distinguish turbulent advective from molecular diffusive processes in order to represent Reynolds and Schmidt number effects. These requirements are addressed here by utilizing two different map-based stochastic turbulence modeling strategies. The one-dimensional turbulence (ODT) model utilizes event-based turbulence modeling, whereas the hierarchical parcel-swapping (HiPS) model is a fully event-based mixing model. ODT provides full-scale resolution at affordable costs by dimensional model reduction based on the boundary-layer approximation to shear flow. HiPS is far less costly than ODT but currently limited to locally homogeneous isotropic turbulence. The physics-compatible modeling capabilities with respect to phase-space representation of turbulent mixing are demonstrated for two canonical cases using standalone model formulations.}, language = {en} } @misc{KleinMedinaMendezSchmidt, author = {Klein, Marten and Medina M{\´e}ndez, Juan Al{\´i} and Schmidt, Heiko}, title = {Stochastic modeling of electrohydrodynamically enhanced drag in one-way and fully coupled turbulent Poiseuille and Couette flow}, series = {Technische Mechanik}, volume = {43}, journal = {Technische Mechanik}, number = {1}, issn = {0232-3869}, doi = {10.24352/UB.OVGU-2023-049}, pages = {111 -- 127}, abstract = {Joint predictive modeling of hydrodynamics and electrokinetics is a standing numerical challenge but crucial for various applications in electrochemistry and power engineering. The present lack in modeling of electrohydrodynamic (EHD) turbulent flows lies in the treatment of small-scale processes and scale interactions. To overcome these limitations, a stochastic one-dimensional turbulence (ODT) model is utilized. The model aims to resolve all scales of the flow, but only on a notional line-of-sight, modeling turbulent advection by a stochastically sampled sequence of eddy events that punctuate deterministic molecular diffusive advancement. In this study, two canonical flow configurations are investigated that address different coupling strategies and flow physics. First, EHD effects in a variable-density vertical pipe flow of an ideal gas with an inner concentric electrode are investigated with a one-way coupled model formulation. Electric fields are generated by means of a corona discharge and the corresponding effect of a fixed ionic charge density field. Second, in order to reduce physical complexity, EHD effects the turbulent boundary layers in plane Couette flow of an isothermal univalent ionic liquid are investigated with a fully coupled model formulation. Both application cases demonstrate that ODT has predictive capabilities due to multiscale resolution of transport processes. Present results suggest that more expensive fully than one-way coupling of electrokinetics is crucial when charge relaxation times are significantly larger than the mean advection time scale.}, language = {en} } @misc{MedinaMendezKleinSchoepsetal., author = {Medina M{\´e}ndez, Juan Ali and Klein, Marten and Sch{\"o}ps, Mark Simon and Schmidt, Heiko}, title = {Predicting volatile wind energy: Stochastic forward modeling and machine learning}, series = {86. Jahrestagung der DPG (86th Annual Conference of the DPG), DPG-Fr{\"u}hjahrstagung 2023, (DPG Spring Meeting 2023 of the Matter and Cosmos Section (SMuK), 20-24 March 2023, Technische Universit{\"a}t Dresden}, journal = {86. Jahrestagung der DPG (86th Annual Conference of the DPG), DPG-Fr{\"u}hjahrstagung 2023, (DPG Spring Meeting 2023 of the Matter and Cosmos Section (SMuK), 20-24 March 2023, Technische Universit{\"a}t Dresden}, publisher = {Deutsche Physikalische Gesellschaft}, address = {Bad Honnef}, issn = {2751-0522}, pages = {S. 343}, language = {en} } @misc{MedinaMendezSchmidt, author = {Medina M{\´e}ndez, Juan Ali and Schmidt, Heiko}, title = {Towards the evaluation of heat and mass transfer in pipe flows with cocurrent falling films using One-Dimensional Turbulence}, series = {Proceedings in Applied Mathematics and Mechanics}, volume = {23}, journal = {Proceedings in Applied Mathematics and Mechanics}, number = {1}, address = {Aachen}, doi = {10.1002/pamm.202200271}, pages = {6}, language = {en} } @misc{KleinMedinaMendezSchmidt, author = {Klein, Marten and Medina M{\´e}ndez, Juan Al{\´i} and Schmidt, Heiko}, title = {Simulating Volatile Wind Energy: Stochastic Forward Modeling and Machine Learning}, publisher = {Innovation Hub 13, TH Wildau}, address = {Wildau}, pages = {1}, abstract = {The transformation of the energy sector is based on the integration of various renewable sources, such as wind and solar energy. One of the key challenges for the integration of these sources into the existing power grid is their erratic and sometimes discontinuous availability (volatility). Wind energy is one of the most relevant sources of CO2 neutral electric energy, but volatile due to fluctuating wind fields on multiple scales. This has already been realized so that senors provide real-time information on the scale of individual wind turbines. However, fore- casting remains an unresolved problem since numerical weather prediction models cannot provide the necessary level of detail. New modeling strategies are required that integrate turbine-scale and meso-scale information for accurate site-specific short-term prediction. Present and forthcoming research aims to incorporate fluctuations on multiple levels of fidelity, depending on the abstraction layer}, language = {en} } @misc{MedinaMendezKleinPeetersetal., author = {Medina M{\´e}ndez, Juan Ali and Klein, Marten and Peeters, Jurriaan W. R. and Schmidt, Heiko}, title = {Evaluating turbulent channel flows with rough walls : homogeneous roughness parameterization for use in a map-based turbulence model}, series = {International journal of heat and fluid flow}, volume = {117, Part B}, journal = {International journal of heat and fluid flow}, publisher = {Elsevier BV}, address = {Amsterdam}, doi = {10.1016/j.ijheatfluidflow.2025.110113}, pages = {1 -- 21}, abstract = {This work is focused on modeling the effects of homogeneous roughness on low-order velocity statistics in turbulent channel flows. Hydrodynamic effects due to the roughness are characterized on the basis of volume-averaging theory (VAT) and a discrete roughness element method. This theory exploits the homogeneous character of the roughness in order to reduce the complexity of the flow to its one-dimensional statistics. The formulated VAT-based roughness forcing is best suited for drag dominated surfaces. Turbulence modeling closure is achieved with a map-based turbulence model, the One-Dimensional Turbulence (ODT) model. This avoids the prescription of laws of the wall or other ad-hoc scalings, unlike in more traditional filter-based turbulence models. The modeling framework is applied on selected Reynolds number flows for likewise selected roughness topologies. Results are compared to direct numerical simulation (DNS) data available from the literature. Among others, model results are compared with those of a previously formulated parametric forcing approach (PFA) for roughness drag which involved a costly coefficient calibration linked to the roughness topology model. In ODT, the only calibration process required is the same one involved for the turbulence model parameters, i.e., similar to the ODT model application for smooth-wall flows. Despite all of the inherently implied shortcomings of a 1-D model, some appealing properties of ODT are discussed. Notably, the model is able to predict the roughness function, as well as the wall-normal profile of the Reynolds shear stress across the entire boundary layer thickness.}, language = {en} } @misc{MedinaMendezKleinSchmidt, author = {Medina M{\´e}ndez, Juan Al{\´i} and Klein, Marten and Schmidt, Heiko}, title = {Fractal roughness representation in a stochastic one-dimensional turbulence modeling approach}, series = {Proceedings of the 13th International Symposium on Turbulence and Shear Flow Phenomena (TSFP13), Montr{\´e}al, Canada, June 25-28, 2024}, journal = {Proceedings of the 13th International Symposium on Turbulence and Shear Flow Phenomena (TSFP13), Montr{\´e}al, Canada, June 25-28, 2024}, pages = {1 -- 6}, language = {en} }