GT-SUITE always runs a Transient simulation. To achieve more stable results from the 1D-3D coupled simulation, the time control on coupling is used. This is achieved by clicking the CFDComponent and the Simulation Phases tab as shown in the Figure 10.90. The user can set one of the following .

• Engine Cycles or Time Before CFD (or “cfdreload”) Started: This denotes the time for which the standalone 1D simulation is performed in GT-SUITE before starting the 1D-3D coupled simulation .
• One-Way Coupled Cycles or Time Ignoring CFD Boundary Data: This denotes the initial time for which the 1D simulation in GT-SUITE ignores the data passed by the coupled 3D simulation.

Figure 10.90 - Time Control - Simulation Phases

In Simerics-MP+

The Time Definition is setup in the Simulation Panel for the CFD simulation as shown in Figure 10.91. The simulation can either be a Steady State Simulation or Transient simulation.

If Simerics-MP+ simulation is set to Steady state, GT Coupling requires to set the timestep for GT corresponding to each Simerics-MP+ iteration, which is set in the Properties Panel as shown in Figure 10.91.

If Simerics-MP+ simulation is set to Transient, the simulation runs for the shorter of the two total times specified in Simerics-MP+ and GT-SUITE. If the CFD Simulation Time (Duration) is more than the GT-SUITE Maximum Simulation Duration (Time), the CFD simulation is stopped, when the Total Simulation Time in GT-SUITE is reached. When Engine Cycles or Time Before CFD is specified in GT-SUITE, the 3D CFD simulation runs for a time equal to (Total Simulation Time - Engine Cycles or Time Before CFD).

The coupled 1D-CFD co-simulation is run in Simerics-MP+ using Start in the Simulation Panel.

Figure 10.91 - Time Control - Coupling

When GT-SUITE simulation is finished, Simerics-MP+ simulation is also terminated and a prompt to save the result file appears.