<?xml version="1.0" encoding="utf-8"?>
<export-example>
  <doc>
    <id>23693</id>
    <completedYear/>
    <publishedYear>2018</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>495</pageFirst>
    <pageLast>520</pageLast>
    <pageNumber/>
    <edition/>
    <issue>4</issue>
    <volume>32</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-03-04</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application</title>
    <abstract language="eng">The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects.</abstract>
    <parentTitle language="eng">Theoretical and Computational Fluid Dynamics</parentTitle>
    <identifier type="doi">10.1007/s00162-018-0465-1</identifier>
    <identifier type="issn">0935-4964</identifier>
    <identifier type="issn">1432-2250</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <author>
      <firstName>David O.</firstName>
      <lastName>Lignell</lastName>
    </author>
    <submitter>
      <firstName>Heiko</firstName>
      <lastName>Schmidt</lastName>
    </submitter>
    <author>
      <firstName>Victoria B.</firstName>
      <lastName>Lansinger</lastName>
    </author>
    <author>
      <firstName>Juan Ali</firstName>
      <lastName>Medina Méndez</lastName>
    </author>
    <author>
      <firstName>Marten</firstName>
      <lastName>Klein</lastName>
    </author>
    <author>
      <firstName>Alan R.</firstName>
      <lastName>Kerstein</lastName>
    </author>
    <author>
      <firstName>Heiko</firstName>
      <lastName>Schmidt</lastName>
    </author>
    <author>
      <firstName>Marco</firstName>
      <lastName>Fistler</lastName>
    </author>
    <author>
      <firstName>Michael</firstName>
      <lastName>Oevermann</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Cylindrical ODT</value>
    </subject>
    <collection role="institutes" number="1311">FG Numerische Mathematik und Wissenschaftliches Rechnen</collection>
    <collection role="institutes" number="3504">FG Numerische Strömungs- und Gasdynamik</collection>
  </doc>
  <doc>
    <id>29338</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>6</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject_ref</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2022-10-03</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Stochastic modeling of three-scalar mixing in a coaxial jet using one-dimensional turbulence</title>
    <abstract language="eng">Modeling complex mixing processes is a standing challenge for a number of applications ranging from chemical to mechanical and environmental engineering. Here, the gas-phase turbulent mixing in a three-stream concentric coaxial jet is investigated as a canonical problem. Reynolds-averaged Navier–Stokes simulations (RANS) suggest that the gas-phase mixing can be accurately modeled by air doped with passive scalars, for which small-scale resolving numerical simulations&#13;
are performed with the one-dimensional turbulence (ODT) model as stand-alone tool. We show that both the spatial (S-ODT) and temporal (T-ODT) model formulations yield qualitatively similar results exhibiting reasonable to good agreement with available reference experiments, Reynolds-averaged and large-eddy simulations, as well as mixing models. This is demonstrated for low-order statistics, like the scalar variance and dissipation, but also the two-scalar joint probability density functions that can not be obtained with RANS. Our results suggest that S-ODT has better capabilities than T-ODT to model the mixing processes in the jet which we attribute to the account of local advective time scales.</abstract>
    <parentTitle language="eng">12th International Symposium on Turbulence and Shear Flow Phenomena (TSFP12), Osaka, Japan (Online), July 19-22, 2022</parentTitle>
    <identifier type="url">http://www.tsfp-conference.org/proceedings/2022/208.pdf</identifier>
    <identifier type="url">http://www.tsfp-conference.org/proceedings/proceedings-of-tsfp-12-2022-osaka.html</identifier>
    <note>Contribution No. 6 of 7 in Session 13C: Jets II</note>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="Artikelnummer">208</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <enrichment key="Fprofil">1 Energiewende und Dekarbonisierung / Energy Transition and Decarbonisation</enrichment>
    <enrichment key="Fprofil">4 Künstliche Intelligenz und Sensorik / Artificial Intelligence and Sensor Technology</enrichment>
    <author>
      <firstName>Marten</firstName>
      <lastName>Klein</lastName>
    </author>
    <submitter>
      <firstName>Marten</firstName>
      <lastName>Klein</lastName>
    </submitter>
    <author>
      <firstName>Christian</firstName>
      <lastName>Zenker</lastName>
    </author>
    <author>
      <firstName>Tommy</firstName>
      <lastName>Starick</lastName>
    </author>
    <author>
      <firstName>Heiko</firstName>
      <lastName>Schmidt</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>stochastic modeling</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>one-dimensional turbulence</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>concentric coaxial round jet</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>multiple passive scalars</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>turbulent mixing</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>co-flow entrainment</value>
    </subject>
    <collection role="institutes" number="1311">FG Numerische Mathematik und Wissenschaftliches Rechnen</collection>
    <collection role="institutes" number="3504">FG Numerische Strömungs- und Gasdynamik</collection>
  </doc>
</export-example>
