Hostname: page-component-76d6cb85b7-8p85h Total loading time: 0 Render date: 2026-07-19T13:21:50.037Z Has data issue: false hasContentIssue false

Direct numerical simulation of a turbulent jet impinging on a heated wall

Published online by Cambridge University Press:  05 January 2015

T. Dairay*
Affiliation:
Turbulence, Mixing and Flow Control Group, Department of Aeronautics, Imperial College London, London SW7 2AZ, UK
V. Fortuné
Affiliation:
Institute PPRIME, Department of Fluid Flow, Heat Transfer and Combustion, CNRS – Université de Poitiers ENSMA, Téléport 2, Boulevard Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil CEDEX, France
E. Lamballais
Affiliation:
Institute PPRIME, Department of Fluid Flow, Heat Transfer and Combustion, CNRS – Université de Poitiers ENSMA, Téléport 2, Boulevard Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil CEDEX, France
L.-E. Brizzi
Affiliation:
Institute PPRIME, Department of Fluid Flow, Heat Transfer and Combustion, CNRS – Université de Poitiers ENSMA, Téléport 2, Boulevard Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil CEDEX, France
*
Email address for correspondence: tdairay@hotmail.fr

Abstract

Direct numerical simulation (DNS) of an impinging jet flow with a nozzle-to-plate distance of two jet diameters and a Reynolds number of 10 000 is carried out at high spatial resolution using high-order numerical methods. The flow configuration is designed to enable the development of a fully turbulent regime with the appearance of a well-marked secondary maximum in the radial distribution of the mean heat transfer. The velocity and temperature statistics are validated with documented experiments. The DNS database is then analysed focusing on the role of unsteady processes to explain the spatial distribution of the heat transfer coefficient at the wall. A phenomenological scenario is proposed on the basis of instantaneous flow visualisations in order to explain the non-monotonic radial evolution of the Nusselt number in the stagnation region. This scenario is then assessed by analysing the wall temperature and the wall shear stress distributions and also through the use of conditional averaging of velocity and temperature fields. On one hand, the heat transfer is primarily driven by the large-scale toroidal primary and secondary vortices emitted periodically. On the other hand, these vortices are subjected to azimuthal distortions associated with the production of radially elongated structures at small scale. These distortions are responsible for the appearance of very high heat transfer zones organised as cold fluid spots on the heated wall. These cold spots are shaped by the radial structures through a filament propagation of the heat transfer. The analysis of probability density functions shows that these strong events are highly intermittent in time and space while contributing essentially to the secondary peak observed in the radial evolution of the Nusselt number.

Information

Type
Papers
Copyright
© 2015 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable