Towards steady-state solutions for supersonic wind accretion on to gravitating objects

Pogorelov, N. V.; Ohsugi, Yukimasa; Matsuda, Takuya

doi:10.1046/j.1365-8711.2000.03199.x

Cited by 52 publications

(43 citation statements)

References 41 publications

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“…We have modified the original conservative form of equations in cylindrical coordinates to obtain a system similar to the system of gas-dynamical equations in Cartesian coordinates. This approach permits us to treat the flow near the axis more accurately (see, e.g., Pogorelov et al 2000). The corresponding equations are:…”

Section: Gas-dynamical Equationsmentioning

confidence: 99%

On the role of duplicity in the Be phenomenon

Harmanec

Bisikalo

Boyarchuk

et al. 2002

A&A

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Abstract. This paper begins a new series of studies devoted to a critical re-examination of the role of duplicity for the Be phenomenon and for the variability patterns observed for many Be stars. Based on both dynamical and energy considerations and a numerical gas-dynamical modelling, a new hypothesis of the formation of Be envelopes in binaries, via an outflow from a rapidly rotating B star in a detached binary, is outlined. It is shown that such an outflow is facilitated by the presence of a companion to the B star and leads to the formation of an envelope but not to any significant mass exchange between the binary components.

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Section: Gas-dynamical Equationsmentioning

confidence: 99%

On the role of duplicity in the Be phenomenon

Harmanec

Bisikalo

Boyarchuk

et al. 2002

A&A

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show abstract

“…The instability observed in numerical simulations seems very weak in 3-D according to Ruffert (1996), whereas it is violent in 2-D (Ishii et al 1993;Shima et al 1998). Pogorelov et al (2000) discussed the possible responsability of the numerical procedure in producing the instability. With a different approach, the instability of the shocked Bondi flow described in this paper could contribute to guide our physical understanding of more complex flows involving isothermal shocks.…”

Section: Introductionmentioning

confidence: 99%

Non-radial instabilities of isothermal Bondi accretion with a shock: Vortical-acoustic cycle vs. post-shock acceleration

Foglizzo

2002

A&A

123

146

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Abstract. The linear stability of isothermal Bondi accretion with a shock is studied analytically in the asymptotic limit of high incident Mach number M 1 . The flow is unstable with respect to radial perturbations as expected by Nakayama (1993), due to post-shock acceleration. Its growth-time scales like the advection time from the shock r sh to the sonic point r son . The growth rate of non-radial perturbations l = 1 is higher by a factor M 2/3 1 , and is therefore intermediate between the advection and acoustic frequencies. Besides these instabilities based on post-shock acceleration, our study revealed another generic mechanism based on the cycle of acoustic and vortical perturbations between the shock and the sonic radius, independently of the sign of postshock acceleration. The vortical-acoustic instability is fundamentally non-radial. It is fed by the efficient excitation of vorticity waves by the isothermal shock perturbed by acoustic waves. The growth rate exceeds the advection frequency by a factor log M 1 . Unstable modes cover a wide range of frequencies from the fundamental acoustic frequency ∼c/r sh up to a cut-off ∼c/r son associated with the sonic radius. The highest growth rate is reached for l = 1 modes near the cut-off. The additional cycle of acoustic waves between the shock and the sonic radius is responsible for variations of the growth rate by a factor up to 3 depending on its phase relative to the vortical-acoustic cycle. The instability also exists, with a similar growth rate, below the fundamental acoustic frequency down to the advection frequency, as vorticity waves are efficiently coupled to the region of pseudosound. These results open new perspectives to address the stability of shocked accretion flows.

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“…However, authors of published papers do not compare their results. For example, different geometrical forms of the bow shock splitting (appearance of different shock branches) were obtained by Myasnikov (1997), Ratkiewicz et al (1998) and Pogorelov and Matsuda (2000) in the simplest axi-symmetric MHD problem (B ∞ ||V ∞ ) and at the same values of boundary conditions. However, numerical results of these authors were not compared neither each other nor with the results by Baranov and Zaitsev (1995) who did not obtain the bow shock splitting.…”

Section: Some Critical Remarksmentioning

confidence: 99%

Kinetic-Fluid Perspective on Modeling the Heliospheric/Interstellar Medium Interface

Баранов

2008

Space Sci Rev

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Content of the invited paper for Workshop "From the Outer Heliosphere to the Local Bubble: Comparison of New Observations with Theory" organized by International Space Science Institute (ISSI) is presented. Main results of the kinetic-fluid model of the solar wind interaction with the partially ionized supersonic flow of the local interstellar medium (LISM) by Baranov and Malama (J. Geophys. Res. 98(A9):15, 163, 1993) and its development by Moscow group to take into account effects of solar cycles, cosmic rays, non-equilibrium processes, magnetic field and so on are given. It is shown that multi-fluid models are not correct for problem considered due to Knudsen number Kn = l ch /L ∼ 1, where l ch is the mean free path of H atoms for collisions connected with the resonance charge exchange, L is the characteristic length of the problem. Important problems connected with the physical properties of the heliospheric boundary and with magnetohydrodynamics (MHD) of the solar wind interaction with the LISM are discussed.

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Towards steady-state solutions for supersonic wind accretion on to gravitating objects

Cited by 52 publications

References 41 publications

On the role of duplicity in the Be phenomenon

On the role of duplicity in the Be phenomenon

Non-radial instabilities of isothermal Bondi accretion with a shock: Vortical-acoustic cycle vs. post-shock acceleration

Kinetic-Fluid Perspective on Modeling the Heliospheric/Interstellar Medium Interface

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