Simulations of Dynamical Gas–Dust Circumstellar Disks: Going Beyond the Epstein Regime

Simulations of Dynamical Gas–Dust Circumstellar Disks: Going Beyond the Epstein Regime Full article

Journal

Astronomy Reports
ISSN: 1063-7729

Output data

Year: 2020, Volume: 64, Number: 2, Pages: 107-125 Pages count : 19 DOI: 10.1134/s1063772920010072

Authors

Stoyanovskaya Olga P. ¹ , Okladnikov Fedor A. ¹ , Vorobyov Eduard I. ² , Pavlyuchenkov Yaroslav N. ³ , Vitaliy V. Akimkin ³

Affiliations

1	Lavrentyev Institute of Hydrodynamics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2	Southern Federal University, Institute of Physics, Rostov-on-Don, Russia
3	Institute of Astronomy, Russian Academy of Sciences, 119017, Moscow, Russia

In circumstellar disks, the size of dust particles varies from submicron to several centimeters, while planetesimals have sizes of hundreds of kilometers. Therefore, various regimes for the aerodynamic drag between solid bodies and gas can be realized in these disks, depending on the grain sizes and velocities: Epstein, Stokes, and Newton, as well as transitional regimes between them. This means that simulations of the dynamics of gas–dust disks require the use of a drag coefficient that is applicable for a wide range for sizes and velocities for the bodies. Furthermore, the need to compute the dynamics of bodies of different sizes in the same way imposes high demands on the numerical method used to find the solution. For example, in the Epstein and Stokes regimes, the force of friction depends linearly on the relative velocity between the gas and bodies, while this dependence is non-linear in the transitional and Newton regimes. On the other hand, for small bodies moving in the Epstein regime, the time required to establish the constant relative velocity between the gas and bodies can be much less than the dynamical time scale for the problem—the time for the rotation of the disk about the central body. In addition, the dust may be concentrated in individual regions of the disk, making it necessary to take into account the transfer of momentum between the dust and gas. It is shown that, for a system of equations for gas and monodisperse dust, a semi-implicit first-order approximation scheme in time in which the interphase interaction is calculated implicitly, while other forces, such as the pressure gradient and gravity are calculated explicitly, is suitable for stiff problems with intense interphase interactions and for computations of the drag in non-linear regimes. The piecewise drag coefficient widely used in astrophysical simulations has a discontinuity at some values of the Mach and Knudsen numbers that are realized in a circumstellar disk. A continuous drag coefficient is presented, which corresponds to experimental dependences obtained for various drag regimes.

Stoyanovskaya O.P. , Okladnikov F.A. , Vorobyov E.I. , Pavlyuchenkov Y.N. , Vitaliy V. Akimkin
Simulations of Dynamical Gas–Dust Circumstellar Disks: Going Beyond the Epstein Regime
Astronomy Reports. 2020. V.64. N2. P.107-125. DOI: 10.1134/s1063772920010072 WOS Scopus РИНЦ OpenAlex

Стояновская О.П. , Окладников Ф.А. , Воробьев Э.И. , Павлюченков Я.Н. , Акимкин В.В.
Расчет динамики газопылевых околозвездных дисков: выход за пределы режима Эпштейна
Astronomy Reports. 2020. V.97. N2. P.91-110. DOI: 10.31857/s0004629920010077 РИНЦ OpenAlex

Submitted:	Jul 17, 2019
Accepted:	Sep 6, 2019
Published print:	Mar 20, 2020

Web of science:	WOS:000520831300001
Scopus:	2-s2.0-85082333330
Elibrary:	43253501
OpenAlex:	W3012145169

DB	Citing
OpenAlex	13
Elibrary	10
Scopus	10
Web of science	11