Avsarkisov, Victor S. (2013)
Turbulent Poiseuille Flow with Uniform Wall Blowing and Suction.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
The objective of this thesis is the analysis of a fully developed, turbulent Poiseuille flow with wall transpiration, i.e. uniform blowing and suction on the lower and upper walls correspondingly. In the present study Lie group analysis of two-point correlation (TPC) equations and a set of Direct Numerical Simulations (DNS) of the three-dimensional, incompressible Navier-Stokes equations are used. The former is applied to find symmetry transformations and in turn to derive invariant solutions of the set of two- and multi-point correlation equations, while the latter is used to simulate turbulent channel flow with wall-transpiration at different Reynolds numbers and transpiration velocities. Both tools are used to find new mean velocity scaling laws. Consequently, it is shown that the transpiration velocity is a symmetry breaking, which implies a logarithmic scaling law in the core region of the channel. DNS validates the result of Lie symmetry analysis and, hence, aids establishing a new logarithmic law of deficit-type. The region of validity of the new logarithmic law is very different from the usual near-wall log-law and the slope constant in the core region differs from the von Karman constant and is equal to 0.3. Apart from the new log-law, extended forms of the linear viscous sublayer law and the near-wall log-law are derived. It is shown that these extended laws, as a particular case, include classical scaling laws obtained for the non-transpirating case. For the near-wall log-law it is found that transpiration only changes the additive constant (C) leaving the von Karman constant unaltered. The results present in the presented thesis indicate that high-Reynolds number and high-transpiration effects counterbalance in the near-wall region and amplify each other in the core region of the flow. It is found that at very high transpiration rates the flow tends to become laminar. Finally, structural analysis of the near-wall regions reveal that wall-blowing boosts generation of hairpin-type vortical structures and amplifies large scale motions (LSMs). Third and forth chapters of the present thesis are heavily based on the paper Avsarkisov, Oberlack & Hoyas (2014).
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2013 | ||||
Autor(en): | Avsarkisov, Victor S. | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Turbulent Poiseuille Flow with Uniform Wall Blowing and Suction. | ||||
Sprache: | Englisch | ||||
Referenten: | Oberlack, Prof. Martin ; Jakirlic, Apl. Prof. Suad | ||||
Publikationsjahr: | 21 August 2013 | ||||
Datum der mündlichen Prüfung: | 5 November 2013 | ||||
URL / URN: | http://tuprints.ulb.tu-darmstadt.de/3931 | ||||
Kurzbeschreibung (Abstract): | The objective of this thesis is the analysis of a fully developed, turbulent Poiseuille flow with wall transpiration, i.e. uniform blowing and suction on the lower and upper walls correspondingly. In the present study Lie group analysis of two-point correlation (TPC) equations and a set of Direct Numerical Simulations (DNS) of the three-dimensional, incompressible Navier-Stokes equations are used. The former is applied to find symmetry transformations and in turn to derive invariant solutions of the set of two- and multi-point correlation equations, while the latter is used to simulate turbulent channel flow with wall-transpiration at different Reynolds numbers and transpiration velocities. Both tools are used to find new mean velocity scaling laws. Consequently, it is shown that the transpiration velocity is a symmetry breaking, which implies a logarithmic scaling law in the core region of the channel. DNS validates the result of Lie symmetry analysis and, hence, aids establishing a new logarithmic law of deficit-type. The region of validity of the new logarithmic law is very different from the usual near-wall log-law and the slope constant in the core region differs from the von Karman constant and is equal to 0.3. Apart from the new log-law, extended forms of the linear viscous sublayer law and the near-wall log-law are derived. It is shown that these extended laws, as a particular case, include classical scaling laws obtained for the non-transpirating case. For the near-wall log-law it is found that transpiration only changes the additive constant (C) leaving the von Karman constant unaltered. The results present in the presented thesis indicate that high-Reynolds number and high-transpiration effects counterbalance in the near-wall region and amplify each other in the core region of the flow. It is found that at very high transpiration rates the flow tends to become laminar. Finally, structural analysis of the near-wall regions reveal that wall-blowing boosts generation of hairpin-type vortical structures and amplifies large scale motions (LSMs). Third and forth chapters of the present thesis are heavily based on the paper Avsarkisov, Oberlack & Hoyas (2014). |
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URN: | urn:nbn:de:tuda-tuprints-39310 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften | ||||
Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Fachgebiet für Strömungsdynamik (fdy) |
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Hinterlegungsdatum: | 01 Jun 2014 19:55 | ||||
Letzte Änderung: | 23 Jun 2014 07:23 | ||||
PPN: | |||||
Referenten: | Oberlack, Prof. Martin ; Jakirlic, Apl. Prof. Suad | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 5 November 2013 | ||||
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