Setting Up Adaptive Time-Stepping

By default, the time-step size is adapted dynamically in the course of an SPH simulation. The time-step size remains as large as possible while at the same time fulfilling the Courant-Friedrichs-Lewy (CFL) condition for stability.

In this simulation, you use Convective CFL and Gravity CFL time-step providers, which adapt the time-step size with respect to the convective and gravitational acceleration contribution. The Viscous CFL time-step provider is only required for SPH simulations that use explicit time integration for the velocity solver—SPH uses implicit time integration by default.
Set up time-step providers for adaptive time-stepping:
  1. Right-click the Continua > Oil Continuum > Models > Adaptive Time-Step > Time-Step Providers node and select New > Convective CFL.
    Here, you can configure the Convective CFL time-step provider for the simulation. By default, the time-step provider is enabled throughout simulation and seeks to maintain a CFL number of 0.72. For this simulation, the default settings are acceptable.
  2. Right-click the Continua > Oil Continuum > Models > Adaptive Time-Step > Time-Step Providers node and select New > Gravity CFL.
    By default, the Gravity CFL time-step provider seeks to maintain a CFL number of 0.073 during the entire simulation.
  3. Save the simulation.