Two-dimensional calculations of tightly wound spiral shocks

Constraining corotation from shocks in tightly-wound spiral galaxies

We present a new method for estimating the corotation radius in tightly wound spiral galaxies, through analysis of the radial variation of the offset between arms traced by the potential (P-arms) and those traced by dust (D-arms). We have verified the predictions of semi-analytical theory through hydrodynamical simulations and have examined the uniqueness of the galactic parameters that can be ...

Nonlinear Dynamics of Two-Dimensional Undercompressive Shocks

Interstellar Turbulence Driving by Galactic Spiral Shocks

Spiral shocks are potentially a major source of turbulence in the interstellar medium. To address this problem quantitatively, we use numerical simulations to investigate gas flow across spiral arms in vertically stratified, self-gravitating, magnetized models of galactic disks. Our models are isothermal, quasi-axisymmetric, and local in the quasi-radial direction while global in the vertical d...

Spiral Shocks in 3D Accretion Discs

We have performed three-dimensional numerical simulations of accretion discs in a close binary system using the Smoothed Particle Hydrodynamics (SPH) method. Our results show that, contrary to previous claims, 3D discs do exist even when the specific heat ratio of the gas is as large as γ = 1.2. Although the disc is clearly more spread in the z-direction in this case than it is for the quasi-is...

Galactic Spiral Shocks with Thermal Instability

Using one-dimensional hydrodynamic simulations including interstellar heating, cooling, and thermal conduction, we investigate nonlinear evolution of gas flow across galactic spiral arms. We model the gas as a non-self-gravitating, unmagnetized fluid, and follow its interaction with a stellar spiral potential in a local frame comoving with the stellar pattern. Initially uniform gas with density...