散逸粒子動力学シミュレーションのための修正周期殻境界条件(流体工学,流体機械)  [in Japanese] Modified Periodic-Shell Boundary Condition for Dissipative Particle Dynamics Simulations(Fluids Engineering)  [in Japanese]

We have developed the modified periodic-shell boundary condition (BC) for dissipative particle dynamics (DPD) simulations, which enables us to simulate an outer flow problem around an obstacle using a small simulation region. In order to clarify the validity of this BC, we have treated a uniform flow around a circular cylinder. The present BC was compared with the ordinary BC such as a uniform flow condition. Also, the present results were compared with those of the numerical results of the Navier-Stokes equations. The ordinary uniform BC is seen to give rise to significantly distorted flow fields and also to significant disappearance of dissipative particles out of the simulation region. In contrast, for the present modified periodic-shell BC, the number density of dissipative particles are kept almost constant during a simulation run, and the flow field is in reasonable agreement with that, which was obtained by the numerical simulations of the Navier-Stokes equations.