Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2010-08-31
Astron. Astrophys. 528, A145 (2011)
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
9 pages, 10 figures, Accepted for publication in A&A
Scientific paper
10.1051/0004-6361/201015661
In the absence of rotation and shear, and under the assumption of constant temperature or specific entropy, purely potential forcing by localized expansion waves is known to produce irrotational flows that have no vorticity. Here we study the production of vorticity under idealized conditions when there is rotation, shear, or baroclinicity, to address the problem of vorticity generation in the interstellar medium in a systematic fashion. We use three-dimensional periodic box numerical simulations to investigate the various effects in isolation. We find that for slow rotation, vorticity production in an isothermal gas is small in the sense that the ratio of the root-mean-square values of vorticity and velocity is small compared with the wavenumber of the energy-carrying motions. For Coriolis numbers above a certain level, vorticity production saturates at a value where the aforementioned ratio becomes comparable with the wavenumber of the energy-carrying motions. Shear also raises the vorticity production, but no saturation is found. When the assumption of isothermality is dropped, there is significant vorticity production by the baroclinic term once the turbulence becomes supersonic. In galaxies, shear and rotation are estimated to be insufficient to produce significant amounts of vorticity, leaving therefore only the baroclinic term as the most favorable candidate. We also demonstrate vorticity production visually as a result of colliding shock fronts.
Brandenburg Axel
Sordo Fabio Del
No associations
LandOfFree
Vorticity production through rotation, shear and baroclinicity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Vorticity production through rotation, shear and baroclinicity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vorticity production through rotation, shear and baroclinicity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-180285