SPH-Based Numerical Study of the Impact of Mudflows on Obstacles

Abstract

In this work, we study the impact of a transient free-surface flow of viscoplastic fluid on a rigid obstacle. This study is conducted numerically using the SPH (Smoothed Particle Hydrodynamics) method, and the Herschel-Bulkley rheological model. The SPH code and its specific adaptations to our needs are presented. The capacity of the code to meet the requirements of our objectives is validated on classic benchmarks. The virtual experiment setup is presented. The local characteristics of the flow near the obstacle, the length of the dead-zone of fluid at rest which forms upstream of the obstacle and the shape of the pressure signal applied to the obstacle are analyzed with reference to the inclination angle and Froude number of the incident flow. This analysis highlights the existence of two impact regimes referred to as the dead-zone and jet impact regimes respectively with a transition occurring for values of the Froude number about 1.3 to 1.5. These values are coherent with previous experimental studies.