On the entrainment assumption in Schatzmann's integral plume model

• Type: Article in International Scientific Journal
• Date: 1997

Authors

Teixeira, MAC (Author) Other; Miranda, PMA (Author) Other

Journal

Title: Flow, Turbulence and Combustion

Vol. 57

Pages: 15-42

ISSN: 1386-6184

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 6 Citations

Scopus - 8 Citations

Other information

Authenticus ID: P-001-C6J

DOI: 10.1007/bf02528762

Abstract (EN): The behaviour of stationary, non-passive plumes can be simulated in a reasonably simple and accurate way by integral models. One of the key requirements of these models, but also one of their less well-founded aspects, is the entrainment assumption, which parameterizes turbulent mixing between the plume and the environment. The entrainment assumption developed by Schatzmann and adjusted to a set of experimental results requires four constants and an ad hoc hypothesis to eliminate undesirable terms. With this assumption, Schatzmann's model exhibits numerical instability for certain cases of plumes with small velocity excesses, due to very fast radius growth. The purpose of this paper is to present an alternative entrainment assumption based on a first-order turbulence closure, which only requires two adjustable constants and seems to solve this problem. The asymptotic behaviour of the new formulation is studied and compared to previous ones. The validation tests presented by Schatzmann are repeated and it is found that the new formulation not only eliminates numerical instability but also predicts more plausible growth rates for jets in co-flowing streams.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 28