Title: accLB: A High-Performance Lattice Boltzmann Code for Multiphase Turbulence on Multi-Gpu Architectures Show Chinese title

Title: accLB：多GPU架构上高性能格子玻尔兹曼方法用于多相湍流的代码

Abstract: In this work, we present accLB, a high-performance Fortran-based lattice Boltzmann (LB) solver tailored to multiphase turbulent flows on multi-GPU architectures. The code couples a conservative phase-field formulation of the Allen-Cahn equation with a thread-safe, regularized LB method to capture complex interface dynamics. Designed from the ground up for HPC environments, accLB employs MPI for distributed memory parallelism and OpenACC for GPU acceleration, achieving excellent portability and scalability on leading pre-exascale systems such as Leonardo and LUMI. Benchmark tests demonstrate strong and weak scaling efficiencies on multiple GPUs. Physical validation includes direct numerical simulations of homogeneous isotropic turbulence (HIT). Further, we examine bubble-laden HIT and observe a transition to a $-3$ energy scaling, as in experiments and theoretical predictions, due to bubble-induced dissipation, along with enhanced small-scale intermittency. These results highlight accLB as a robust and scalable platform for the simulation of multiphase turbulence in extreme computational regimes. Show Chinese abstract

Abstract: 在这项工作中，我们提出了 accLB，这是一种高性能的基于 Fortran 的格子玻尔兹曼（LB）求解器，专门针对多 GPU 架构上的多相湍流流动。该代码将 Allen-Cahn 方程的保守相场公式与线程安全的正则化 LB 方法结合，以捕捉复杂的界面动力学。accLB 从底层为高性能计算（HPC）环境设计，使用 MPI 进行分布式内存并行，并使用 OpenACC 进行 GPU 加速，在领先的前百亿亿次系统（如 Leonardo 和 LUMI）上实现了出色的可移植性和可扩展性。基准测试展示了多个 GPU 上的强大和弱扩展效率。物理验证包括同质各向同性湍流（HIT）的直接数值模拟。此外，我们检查了气泡负载的 HIT，并观察到由于气泡诱导的耗散，能量标度过渡到 $-3$，这与实验和理论预测一致，同时伴随着增强的小尺度间歇性。这些结果突显了 accLB 作为模拟极端计算条件下多相湍流的稳健且可扩展平台的重要性。