The University of Southampton
University of Southampton Institutional Repository

Comprehensive characterisation of turbulence dynamics with emphasis on wall-bounded flows

Comprehensive characterisation of turbulence dynamics with emphasis on wall-bounded flows
Comprehensive characterisation of turbulence dynamics with emphasis on wall-bounded flows
This report describes the work carried out in `universality' aspects of the dynamics of turbulence in compressible flows. Direct numerical simulations (DNSs) are carried out in different inhomogeneous and anisotropic flows. All discussed flows show regions of strong imbalance of turbulent production and turbulent dissipation. This distinguishes this work from most studies in the literature about the fundamentals of turbulent dynamics. A characteristic decomposition in addition to temporal and spatial filtering are applied as tools to compare differences in the turbulent dynamics across different flow topologies. The work includes a discussion about universal aspects of the velocity gradient and related quantities in a turbulent boundary layer, in a jet flow as well as in a wake flow. Invariant features are highlighted and quantified and the differences are pointed out. The velocity gradient and the enstrophy production, as one of the key quantities in the turbulent energy cascading process, are discussed in great detail in the turbulent boundary layer flow. Focus hereby is on the wall-normal development of the structure of the enstrophy production. This is followed by a comprehensive overview of a turbulent boundary layer. This includes the presentation and discussion of global energy redistributing mechanisms from different perspectives. The key role of turbulence in these processes is made clear. The energy cascade is dissected at different locations which reveals three different transfer processes. Two of which are transferring energy from larger scales of motion towards smaller scales of motion. In addition a backscatter mechanism was discovered that transfers energy from smaller scales towards larger scales of motion. Besides this some specific and potentially universal features of turbulence within the turbulent boundary layer results are discussed.
Bechlars, Patrick
995297cf-a7ca-479f-889b-50babdf247bb
Bechlars, Patrick
995297cf-a7ca-479f-889b-50babdf247bb
Sandberg, Richard
41d03f60-5d12-4f2d-a40a-8ff89ef01cfa

Bechlars, Patrick (2015) Comprehensive characterisation of turbulence dynamics with emphasis on wall-bounded flows. University of Southampton, Engineering and the Environment, Doctoral Thesis, 305pp.

Record type: Thesis (Doctoral)

Abstract

This report describes the work carried out in `universality' aspects of the dynamics of turbulence in compressible flows. Direct numerical simulations (DNSs) are carried out in different inhomogeneous and anisotropic flows. All discussed flows show regions of strong imbalance of turbulent production and turbulent dissipation. This distinguishes this work from most studies in the literature about the fundamentals of turbulent dynamics. A characteristic decomposition in addition to temporal and spatial filtering are applied as tools to compare differences in the turbulent dynamics across different flow topologies. The work includes a discussion about universal aspects of the velocity gradient and related quantities in a turbulent boundary layer, in a jet flow as well as in a wake flow. Invariant features are highlighted and quantified and the differences are pointed out. The velocity gradient and the enstrophy production, as one of the key quantities in the turbulent energy cascading process, are discussed in great detail in the turbulent boundary layer flow. Focus hereby is on the wall-normal development of the structure of the enstrophy production. This is followed by a comprehensive overview of a turbulent boundary layer. This includes the presentation and discussion of global energy redistributing mechanisms from different perspectives. The key role of turbulence in these processes is made clear. The energy cascade is dissected at different locations which reveals three different transfer processes. Two of which are transferring energy from larger scales of motion towards smaller scales of motion. In addition a backscatter mechanism was discovered that transfers energy from smaller scales towards larger scales of motion. Besides this some specific and potentially universal features of turbulence within the turbulent boundary layer results are discussed.

PDF
Thesis_Bechlars_111115.pdf - Other
Download (61MB)

More information

Published date: November 2015
Organisations: University of Southampton, Aerodynamics & Flight Mechanics Group

Identifiers

Local EPrints ID: 388096
URI: https://eprints.soton.ac.uk/id/eprint/388096
PURE UUID: 25ecf69f-36b3-4ec5-97f4-f0fc871c694d
ORCID for Richard Sandberg: ORCID iD orcid.org/0000-0001-5199-3944

Catalogue record

Date deposited: 22 Feb 2016 13:37
Last modified: 14 Jun 2019 00:35

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×