A better understanding of the hydrodynamics of the cerebrospinal fluid (CSF) is important to understand the pathophysiology of various diseases related to the central nervous system (CNS). This project aims to simulate the CSF flow in subject specific subarachnoid spaces (SAS) of healthy volunteers and patients suffering from Chiari malformation. The simulations at high spatial and temporal resolutions are conducted using the Lattice Boltzmann Method (LBM) based solver Musubi, which is ported on the SX-ACE for efficient and scalable direct numerical simulation of the CSF. In this report, implementation and performance analysis of MUSUBI on SX-ACE are presented. Basic Information (1) Collaborating JHPCN Centers Cyberscience Center, Tohoku University.