Once you have determined that a running a two-way coupled analysis is your objective, it is recommended that you build up to the final two-way analysis incrementally, progressively adding complexity with each step. The following sequence of steps is recommended for building any coupled analysis:
- Step 1: Solve each participant problem individually as a decoupled analysis.
Before coupling your participant problems, verify that each one of them can be solved individually, as decoupled solutions. By running each one independently, you can get an approximation of their expected inputs to a coupled analysis.
As much as possible, try to set up the decoupled analyses so that they replicate the participants' expected roles in the prospective coupled analyses. (For example, to prepare for an FSI analysis, you would apply a pressure load in the structural analysis or set up mesh motion and deformation in the fluid analysis.)
Once you have verified that each of the problems can be solved individually on its own, you can proceed to working with one-way coupled analyses.
- Step 2: Solve each participant problem as part of a one-way coupled analysis.
Verify that each of the participant problems can be run successfully as part of a one-way coupled analysis. To do this, create a one-way coupled analysis for each participant problem and use the results of the other participant's decoupled run as inputs, approximating the values it may receive in a two-way coupled analysis. This allows you to assess the sensitivity of each participant's analysis to the expected inputs.
The one-way coupled analyses should replicate the effects of the intended two-way coupled analysis as closely as possible. If one or both problems show sensitivity to the inputs it receives, then further exploration via a two-way coupled analysis may be useful.
Once the one-way analyses have been solved, how you proceed depends on your end goal for the problem:
If a one-way coupled analysis is your end goal, then the next step is to evaluate its convergence. For information on assessing coupled analysis convergence, see Evaluating Convergence and Data Transfer Accuracy. For participant-specific methods of evaluating convergence, see the relevant participant product documentation.
If a two-way coupled analysis is your end goal, then proceed to the creation of the two-way analysis.
- Step 3: Solve both participant problems as a two-way coupled analysis.
Solve both participant problems as a two-way coupled analysis. To do this, remove the approximated inputs used for the one-way analyses and then incorporate each participant problem into the two-way simulation.
For an illustration of how these steps might be used for a specific application, see Building a Coupled FSI Analysis from Decoupled Participant Problems.