*2.4. The Mathematical Simulation Model*

The numerical simulation model is built by a steady state solver, and then the erosion of particles is calculated by a transient solver. There are five physical field interfaces and two multi-physics interfaces in the model: turbulent flow (*spf*), particle tracking for fluid flow (*fpt*), chemistry (*chem*), secondary current distribution (*siec*), transport of diluted species (*tds*), fluid-particle interaction (*fpi*), and flow coupling (*fc*). The *chem* interface is a physical field interface in the numerical simulation software, and the *siec* interface as same.
