円盤銀河の渦状衝撃波構造Wiggle instabilityの再検討(宇宙・惑星(2),一般講演)

概要

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We have reexamined the wiggle instability of gas flow in spiral galaxies based on numerical sumulations. The wiggle instability, which was discoverd by Wada and his collaborators, disturbs shcck compressed gas in the numerical simulations of spiral galaxies. It is confirmed by other groups and is thought to appear independently of the numercial scheme adopted. Here we show that the wiggle instability is of numerical origin and can be suppressed by modifying variable intepolation for higher order numerical flux. In the wiggle instability free simulations, the variables are linierly interpolated only when the gradient is lower than a certain upper limit, e.g., 10% of the sound speed per cell. We discuss the validity of the upper limit in the text.
2010-09-09