WaLBerla: Exploiting Massively Parallel Systems for Lattice Boltzmann Simulations

In this chapter, a software concept for massively parallel computational fluid dynamics (CFD) applications is introduced. The focus thereby lies on the parallelization, which is based on a domain partitioning scheme named patch concept. This concept also enables a seamless specialization of the partitions to different application features as well as the possibility for further optimization such as memory reduction. It is discussed in detail how our design ensures an efficient and flexible implementation. The suitability and efficiency of this concept is demonstrated and evaluated with the waLBerla project, which aims at the development of an efficient massively parallel lattice Boltzmann framework providing the necessary features for several CFD applications. To discuss the suitability of the parallelization for massively parallel usage, various test scenarios have been investigated on different architectures. These tests include serial, weak and strong scaling experiments up to 810 cores and up to a domain size of 15303 lattice cells.