The Jeans instability in smoothed particle hydrodynamics
The Jeans instability in smoothed particle hydrodynamics
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平滑粒子流体动力学中的 Jeans 不稳定性
DOI：
10.1046/j.1365-8711.1998.01479.x
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发表时间：
1998
影响因子：
4.8
通讯作者：
A. Whitworth
中科院分区：
文献类型：
--
作者：
A. Whitworth
我们推导出解析的金斯标准的气体模拟使用SPH代码中的邻居Nmb的数量保持不变（近似）和重力软化长度，e，等于平滑长度，h（近似）。我们表明，准确地再现解析结构，即那些代表的> NH4B粒子的牛仔裤标准。未分辨的结构是稳定的，只要（i）平滑核W（u）是足够的中心峰值，（ii）金斯质量是解决。如果这些条件都得到满足，那么在模拟恒星和星系的形成过程中，任何发生的碎裂都应该是物理的，并且是可分辨的。特别是不应该有由于数值不稳定性的亚金斯凝聚的创建。
We derive analytically the Jeans criterion for a gas simulated using an SPH code in which the number of neighbours Nneighb is held constant (approximately) and the gravity-softening length, e, equals the smoothing length, h (approximately). We show that the Jeans criterion is reproduced accurately for resolved structures, i.e. those represented by > Nneighb particles. Unresolved structures are stabilized, as long as (i) the smoothing kernel W(u) is sufficiently centrally peaked, and (ii) the Jeans mass is resolved. Provided that these conditions are satisfied, then, in simulations of the formation of stars and galaxies, any fragmentation that occurs should be both physical and resolved. In particular there should be no creation of sub-Jeans condensations owing to numerical instability.