The University of Southampton
University of Southampton Institutional Repository

Flow evolution and mass transfer in a turbulent rectangular free jet of air with small laminar Schmidt number

Flow evolution and mass transfer in a turbulent rectangular free jet of air with small laminar Schmidt number
Flow evolution and mass transfer in a turbulent rectangular free jet of air with small laminar Schmidt number

Numerical results are presented for flow evolution, mass transfer and evaluation of the turbulent Schmidt number in a turbulent submerged free jet of air with small laminar Schmidt number (Sc = 0.1). A series of Large Eddy Simulation (LES) are carried on in the Reynolds number range from 5000 to 40,000. The numerical results are reported in terms of instantaneous and mean velocities, static pressure, passive scalar fields and turbulent Schmidt number. The numerical results show that the instantaneous cross-stream velocity and the static pressure are null in the Negligible Disturbance Flow (NDF) and the Small Disturbance Flow (SDF) of the instantaneous jet evolution, allowing a new definition of NDF and SDF. Similarly, the numerical mean static pressure is null in the Undisturbed Region of Flow (URF) of the mean evolution, allowing a new definition of URF. The turbulent Schmidt number shows differences at the two smallest Reynolds numbers, Re = 5000 and 10,000, in comparison to the previous numerical results, obtained with a laminar Schmidt number equal to Sc = 1. A theoretical model is proposed for the passive scalar diffusion in the Undisturbed Region of Flow (URF) and the Potential Core Region (PCR), under the hypotheses of self-similarity, according to the Tollmien and Görtler approaches. The solutions of the present theoretical models, at Sc = 0.1, are self-similar in the PCR and in good agreement with the LES numerical results of the passive scalar, while the passive scalar profiles are not self-similar in the URF at the smaller Reynolds numbers, differently from what happens with a laminar Schmidt number in the range 1–100. The theoretical model assumes a turbulent Schmidt number inversely proportional to the mean velocity gradient in the PCR, as suggested by the LES results. The numerical results of the ScT in the URF are variable in the range 0–0.85, which is a value commonly suggested in the literature. In the PCR the values of ScT are variable between zero and a maximum which is one order of magnitude greater than in the URF.

Flow evolution, mass transfer and evaluation of the turbulent Schmidt number, Large Eddy simulation of turbulent submerged rectangular free jet of air with Sc = 0.1, New definition of negligible disturbance flow (NDF) and small disturbance flow (SDF), New definition of undisturbed region flow (URF), Passive scalar diffusion not self-similar in undisturbed region flow (URF) for Sc = 0.1
0735-1933
44-54
Venuta, Ivan Di
c478ec72-9e42-45cd-9afb-147f93b6835b
Boghi, Andrea
54a72da6-c8a2-468c-9773-897efac0638f
Petracci, Ivano
dac18404-ee75-45ea-9d27-dcbe9faef2cd
Bartoli, Carlo
d1aa084e-73b4-4d96-aacc-0c729b1bf77d
Gori, Fabio
f7e76614-37d8-4c3b-b7b0-8c6603a4515f
Venuta, Ivan Di
c478ec72-9e42-45cd-9afb-147f93b6835b
Boghi, Andrea
54a72da6-c8a2-468c-9773-897efac0638f
Petracci, Ivano
dac18404-ee75-45ea-9d27-dcbe9faef2cd
Bartoli, Carlo
d1aa084e-73b4-4d96-aacc-0c729b1bf77d
Gori, Fabio
f7e76614-37d8-4c3b-b7b0-8c6603a4515f

Venuta, Ivan Di, Boghi, Andrea, Petracci, Ivano, Bartoli, Carlo and Gori, Fabio (2019) Flow evolution and mass transfer in a turbulent rectangular free jet of air with small laminar Schmidt number. International Communications in Heat and Mass Transfer, 107, 44-54. (doi:10.1016/j.icheatmasstransfer.2019.06.001).

Record type: Article

Abstract

Numerical results are presented for flow evolution, mass transfer and evaluation of the turbulent Schmidt number in a turbulent submerged free jet of air with small laminar Schmidt number (Sc = 0.1). A series of Large Eddy Simulation (LES) are carried on in the Reynolds number range from 5000 to 40,000. The numerical results are reported in terms of instantaneous and mean velocities, static pressure, passive scalar fields and turbulent Schmidt number. The numerical results show that the instantaneous cross-stream velocity and the static pressure are null in the Negligible Disturbance Flow (NDF) and the Small Disturbance Flow (SDF) of the instantaneous jet evolution, allowing a new definition of NDF and SDF. Similarly, the numerical mean static pressure is null in the Undisturbed Region of Flow (URF) of the mean evolution, allowing a new definition of URF. The turbulent Schmidt number shows differences at the two smallest Reynolds numbers, Re = 5000 and 10,000, in comparison to the previous numerical results, obtained with a laminar Schmidt number equal to Sc = 1. A theoretical model is proposed for the passive scalar diffusion in the Undisturbed Region of Flow (URF) and the Potential Core Region (PCR), under the hypotheses of self-similarity, according to the Tollmien and Görtler approaches. The solutions of the present theoretical models, at Sc = 0.1, are self-similar in the PCR and in good agreement with the LES numerical results of the passive scalar, while the passive scalar profiles are not self-similar in the URF at the smaller Reynolds numbers, differently from what happens with a laminar Schmidt number in the range 1–100. The theoretical model assumes a turbulent Schmidt number inversely proportional to the mean velocity gradient in the PCR, as suggested by the LES results. The numerical results of the ScT in the URF are variable in the range 0–0.85, which is a value commonly suggested in the literature. In the PCR the values of ScT are variable between zero and a maximum which is one order of magnitude greater than in the URF.

Full text not available from this repository.

More information

e-pub ahead of print date: 10 June 2019
Published date: 1 October 2019
Keywords: Flow evolution, mass transfer and evaluation of the turbulent Schmidt number, Large Eddy simulation of turbulent submerged rectangular free jet of air with Sc = 0.1, New definition of negligible disturbance flow (NDF) and small disturbance flow (SDF), New definition of undisturbed region flow (URF), Passive scalar diffusion not self-similar in undisturbed region flow (URF) for Sc = 0.1

Identifiers

Local EPrints ID: 434185
URI: http://eprints.soton.ac.uk/id/eprint/434185
ISSN: 0735-1933
PURE UUID: fefd469b-f4e6-488e-9481-dd4b4ed19a5d
ORCID for Andrea Boghi: ORCID iD orcid.org/0000-0002-9387-326X

Catalogue record

Date deposited: 13 Sep 2019 16:30
Last modified: 07 Oct 2020 01:10

Export record

Altmetrics

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 http://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.

×