Study on Dynamical Evolution of Dense Stellar Systems with Special Purpose Computers.

1991学年博士牧野访问了爱丁堡大学，并与Heggie、McMillan和Aarseth博士（剑桥大学）合作，开发了一种用于特殊用途计算机GRAPE模拟的Hermite积分代码。McMillan博士访问了东京大学，并与Inagaki博士合作在GRAPE-2A上实现了他的星团模拟程序。Hunquist博士还访问了东京大学，并在GRAPE-2A上实现了他的SPH代码。1992学年Makino、Hut和Hunquist博士系统地研究了无碰撞引力系统中树型程序的误差。他们发现树代码为引力N体模拟提供了足够高的精度。八须博士发明了一种涡旋动力学 关于我们 不可压缩流体模拟的并行程序。他发现GRAPE系统可以大大加速涡旋动力学模拟以及引力N体模拟。1993学年我们在东京大学驹场校区举办了一个关于致密恒星系统动力学演化和专用计算机开发的研讨会，总结了三年合作的结果。我们的结论是，恒星的直接碰撞在致密恒星系统中起着重要的作用。Hachisu、Ueno和Miyama博士研究了各种类型的计算流体动力学代码，并得出结论，Gudnov型SPH方法最适合于专用计算机模拟自引力流体。SPH专用计算机的概念和详细设计是在东京大学和国家天文台的合作下完成的。在1994学年，我们将制作SPH机的测试板，并开始研制SPH码专用大规模集成电路。少

Academic Year 1991Dr. Makino visited University of Edinburgh and developed a Hermite integration code for the simulations with the special purpose computer, GRAPE, in collaboration with Drs. Heggie, McMillan, and Aarseth (Cambridge University). This code is simpler and more suitable to GRAPE than the Aarseth code, which has been widely used in the N-body simulations of collisional gravitational systems.Dr.McMillan visited University of Tokyo and implemented his simulation code for stellar cluster to GRAPE-2A in collaboration with Dr.Inagaki. Dr.Hunquist also visited in University of Tokyo and implemented his SPH code to GRAPE-2A. They confirmed that GRAPE systems are suitable to the use of both two codes.Academic Year 1992Drs.Makino, Hut, and Hunquist systematically investigated the error in the tree code, which is used in collisionless gravitational systems. They found the tree code offers an accuracy high enough for gravitational N-body simulations. Dr.Hachisu developed a vortex dyna … More mics code of incompressible fluid simulations. He found that GRAPE systems can greatly accelerate the vortex dynamics simulations as well as gravitational N-body simulations.Academic Year 1993We held a workshop on the dynamical evolution of dense stellar systems and the development of special purpose computers to summarize the results of three-years collaborations in Komaba campus University of Tokyo. We concluded that the direct collision of stars plays an important role in dense stellar systems. Drs.Hachisu, Ueno, and Miyama investigated the various types of computational fluid dynamics codes and concluded that the Gudnov type SPH method is most suitable to the special purpose computers for the simulations of self-gravitational fluid. The conceptual and detailed designs of the special purpose computer for SPH were done in collaboration of University of Tokyo and National Astronomical Observatory. In the academic year 1994, we shall make a test board of SPH machine and start to develop a special purpose LSI for the SPH code. Less