I am making a simulation of a molten metal droplet that impacts a substrate. I am using a coupled euelerian lagrangian approach (CEL). My simulation has run for several days but it does not converge. The stable increment time is really really small. I would like to know if there are numerical tools that I can use to having larger stable time increments ?  If there is any tool which are the precautions that I should take into account to make a good use of this tool and not take away the physical sense of my simulation?