Toggle Main Menu Toggle Search

Open Access padlockePrints

Evolution of highly buoyant thermals in a stratified layer

Lookup NU author(s): Professor Axel Brandenburg


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


The buoyant rise of thermals (i.e. bubbles of enhanced entropy, but initially in pressure equilibrium) is investigated numerically in three dimensions for the case of an adiabatically stratified layer covering 6-9 pressure scale heights. It is found that these bubbles can travel to large heights before being braked by the excess pressure that builds up in order to drive the gas sideways in the head of the bubble. Until this happens, the momentum of the bubble grows as described by the time-integrated buoyancy force. This validates the simple theory of bubble dynamics whereby the mass entrainment of the bubble provides an effective braking force well before the bubble stops ascending. This is quantified by an entrainment parameter alpha which is calculated from the simulations and is found to be in good agreement with the experimental measurements. This work is discussed in the context of contact binaries whose secondaries could be subject to dissipative heating in the outermost layers.

Publication metadata

Author(s): Brandenburg A, Hazlehurst J

Publication type: Article

Publication status: Published

Journal: Astronomy and Astrophysics

Year: 2001

Volume: 370

Issue: 3

Pages: 1092-1102

ISSN (print): 0004-6361

ISSN (electronic): 1432-0746

Publisher: EDP Sciences


DOI: 10.1051/0004-6361:20010273


Altmetrics provided by Altmetric