Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993mnras.265..905n&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Vol. 265, NO. 4/DEC15, P. 905, 1993
Astronomy and Astrophysics
Astronomy
72
Hydrodynamics - Instabilities - Methods: Numerical - Binaries: General - Stars: Formation
Scientific paper
We present the results of collapse calculations for elongated clouds performed using the numerical method of smoothed particle hydrodynamics (SPH). The clouds considered are isothermal, prolate spheroids with different axial ratios (a/b). Results are obtained for different values of a/b and mbarL, the mean mass per unit length. It is found that initially uniform clouds undergo fragmentation when the collapse is preferentially down on to the major axis, due to the intrinsic instability of a linear configuration. This occurs when the value of mbarL is sufficiently large. A criterion for elongated clouds to undergo linear collapse is derived using the tensor virial theorem, and it is found that the numerically obtained value of mbarL for which fragmentation occurs corresponds closely to that expected from analytical considerations. The addition of small density perturbations simply results in clouds that fragment more easily, particularly for cases in which a/b is close to unity.
Previous calculations, presented by other authors for the case of finite cylinders, show that clouds with cylindrical geometries are highly unstable to the formation of two fragments that occur at the ends of the cylinder. We find that collapsing, prolate spheroids show qualitatively different behaviour, with no preferred tendency to form fragments at the ends of the cloud. Instead fragmentation appears to occur more readily towards the centre of the cloud where the local mass per unit length is greatest.
Our implementation of SPH employs spatially variable smoothing lengths, h. In order to obtain a Hamiltonian system, we incorporate terms involving the spatial variability of h in the particle equations of motion, not included in previous implementations. We find that inclusion of these ∇h terms results in much improved energy conservation, but has little effect on the qualitative outcome of the calculations presented here. (fset 'queer "∇")
Nelson Richard P.
Papaloizou John C. B.
No associations
LandOfFree
Three-Dimensional Hydrodynamic Simulations of Collapsing Prolate Clouds 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 Three-Dimensional Hydrodynamic Simulations of Collapsing Prolate Clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-Dimensional Hydrodynamic Simulations of Collapsing Prolate Clouds will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1300561