Three-Dimensional Parallel Simulations of the Scour Around Multiple Cylinders

The study of flow around single or multiple piles has been conducted extensively due to its significance in both engineering applications and fluid mechanics. In this work, we aim to investigate cases involving multiple piles at different positions and examine how they differ from more extensively studied scenarios, such as a single circular cylinder in a wide channel. Our approach involves solving three-dimensional Navier-Stokes-Exner equations on arbitrary geometries. The numerical formulation is based on a projection method, and the discretization is obtained by combining a second-order unstructured finite-volume method and a sigma transformation. However, three-dimensional simulations are computationally expensive, especially when investigating long-term behaviors such as scour around structures. To address this challenge, we introduce an MPI parallelization technique to enhance the Multi-Color Successive Over-Relaxation method using a block domain decomposition. We validate the code by solving the three-dimensional problem and comparing the results against well-established benchmarks featuring complex flows. Specifically, in this paper, we focus on an equilateral-triangular configuration involving three circular cylinders.