Zu kohärenten Turbulenzstrukturen in der Strömung gegliederter Gerinne

Rivers are an integral part of our environment. Due to different demands in term of utilisation as well as protection an efficient water management is essential. This can only be achieved by a fundamental knowledge of the governing hydro-dynamical processes. In this thesis, the existence of time-dependent organised phenomena, so-called coherent turbulent structures is proved experimentally and these structures are further investigated. A spatial and temporal resolving experimental set-up based on the Particle-Image Velocimetry is used. For detection of the coherent turbulent structures a special method has been developed, which enables to reliable identify the structures and to evaluate them in quantitative matters. Based on this detection-method the regularly appearance of coherent turbulent structures in the shear zone between main channel and adjacent flood plain can be shown. The coherent structures appear to have a three-dimensional shape with a horizontal vortex and a secondary current as their main elements. The internal set-up consists of a vortex core and an outer region which interacts with the surrounding flow field. The coherent turbulent structures are identified to be the dominant flow phenomenon by applying an advanced filter technique to the instantaneous flow fields. Accordingly, the characteristic flow structure in compound channels described by multiple authors- shear zone, secondary currents and high turbulence intensity - can be explained physically by the coherent structures. They also influence the turbulent energy budget by generating a strong production of turbulent kinetic energy within the interaction zone. This net generation of energy is distributed by secondary flows and turbulence fluctuations. The research presented in the thesis on hand could prove the existence of coherent turbulent structures in the shear zone of compound open channels. The appropriate experimental set-up as well as reliable methods have been developed for further studies. Especially a more detailed quantitative description of the structures themselves and also their temporal development are of interest. Based on these results, in the future coherent turbulent structures will be taken into consideration on a physical basis for dealing with practical water management tasks.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• von Lukowicz, Joachim

Contributors dc:contributor

• Köngeter, Jürgen

• info:eu-repo/classification/ddc/550
• Offenes Gerinne
• Gerinneströmung
• Turbulente Strömung
• Kohärenz
• Strömungsfeld
• Geowissenschaften
• Turbulenz
• kohärente Strukturen
• offene Fließgewässer
• PIV
• Wirbel

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123144%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:61483