26.12 Performing Time-Dependent Calculations

ANSYS FLUENT can solve the conservation equations in a time-dependent manner, to simulate a wide variety of time-dependent phenomena, such as

• vortex shedding and other time-periodic phenomena

• compressible filling and emptying problems

• transient heat conduction

• transient chemical mixing and reactions

Figures  26.12.1 and 26.12.2 illustrate the time-dependent vortex shedding flow pattern in the wake of a cylinder.

Figure 26.12.1: Time-Dependent Calculation of Vortex Shedding ( $t$=36.6 sec)

Figure 26.12.2: Time-Dependent Calculation of Vortex Shedding ( $t$=41.6 sec)

Activating time dependence is sometimes useful when attempting to solve steady-state problems which tend toward instability (e.g., natural convection problems in which the Rayleigh number is close to the transition region). It is possible in many cases to reach a steady-state solution by integrating the time-dependent equations.

For details about temporal discretization, see this section in the separate Theory Guide.