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Compressive and extensive strain along gradient trajectories

Gampert, Markus ; Goebbert, Jens Henrik ; Schaefer, Philip ; Gauding, Michael ; Peters, Norbert ; Aldudak, Fettah ; Oberlack, Martin (2024)
Compressive and extensive strain along gradient trajectories.
In: Journal of Physics: Conference Series, 2011, 318 (5)
doi: 10.26083/tuprints-00020772
Article, Secondary publication, Publisher's Version

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Item Type: Article
Type of entry: Secondary publication
Title: Compressive and extensive strain along gradient trajectories
Language: English
Date: 6 February 2024
Place of Publication: Darmstadt
Year of primary publication: 2011
Place of primary publication: Bristol
Publisher: IOP Publishing
Journal or Publication Title: Journal of Physics: Conference Series
Volume of the journal: 318
Issue Number: 5
Collation: 11 Seiten
DOI: 10.26083/tuprints-00020772
Corresponding Links:
Origin: Secondary publication DeepGreen
Abstract:

Based on direct numerical simulations of forced turbulence, shear turbulence, decaying turbulence, a turbulent channel flow as well as a Kolmogorov flow with Taylor based Reynolds numbers Reλ between 69 and 295, the normalized probability density function of the length distribution P̃(l̃) of dissipation elements, the conditional mean scalar difference < Δk | l > at the extreme points as well as the scaling of the two-point velocity difference along gradient trajectories < Δun> are studied. Using the field of the instantanous turbulent kinetic energy k as a scalar, we find a good agreement between the model equation for P̃(l̃) as proposed by Wang and Peters (2008) and the results obtained in the different DNS cases. This confirms the independance of the model solution from both, the Reynolds number and the type of turbulent flow, so that it can be considered universally valid. In addition, we show a 2/3 scaling for the mean conditional scalar difference. In the second part of the paper, we examine the scaling of the conditional two-point velocity difference along gradient trajectories. In particular, we compare the linear s/τ scaling, where τ denotes an integral time scale and s the separation arclength along a gradient trajectory in the inertial range as derived by Wang (2009) with the s · a∞ scaling, where a∞ denotes the asymtotic value of the conditional mean strain rate of large dissipation elements.

Identification Number: Artikel-ID: 052029
Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-207721
Additional Information:

13th European Turbulence Conference (ETC13)

Classification DDC: 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering
Divisions: 16 Department of Mechanical Engineering > Fluid Dynamics (fdy)
Date Deposited: 06 Feb 2024 10:05
Last Modified: 30 Apr 2024 12:25
SWORD Depositor: Deep Green
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/20772
PPN: 517568624
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