A Scalable Numerical Method for Simulating Flows Around High-Speed Train Under Crosswind Conditions

This paper presents a parallel Newton-Krylov-Schwarz method for the numerical simulation of unsteady flows at high Reynolds number around a high-speed train under crosswind.With a realistic train geometry,a realistic Reynolds number,and a realistic wind speed,this is a very challenging computational problem.Because of the limited parallel scalability,commercial CFD software is not suitable for supercomputers with a large number of processors.We develop a Newton-KrylovSchwarz based fully implicit method,and the corresponding parallel software,for the 3D unsteady incompressible Navier-Stokes equations discretized with a stabilized finite element method on very fine unstructured meshes.We test the algorithm and software for flows passing a train modeled after China’s high-speed train CRH380B,and we also compare our results with results obtained from commercial CFD software.Our algorithm shows very good parallel scalability on a supercomputer with over one thousand processors.