Importing results as initial conditions can enable you to define the initial state of the
current analysis case faster. When you import results, you can import the current set of
results from an analysis case or a previous set, and you can import results from the end of
the analysis case or from the end of one of its steps. You can also import values for all
field output variables in the source analysis case or from a selected subset of them.
Importing results as initial conditions offers the following advantages as you set up a
simulation:
- Using imported results can reduce simulation time in the long run. You can perform a
simulation with a coarse mesh first, then refine its mesh and perform a new simulation with
the finer mesh using the import capability. In general, starting with better initial
conditions reduces the total number of iterations to achieve convergence, and imported
results provide better initial conditions than a uniform initial value. The simulation time
saved from reducing the number of iterations from the fine case can exceed the extra cost of
running the coarse simulation. For example, in an analysis where the energy field is
progressing mostly by diffusion, the simulation can require many iterations to reach the
final distribution. By providing a good initial solution from a converged coarse solution,
the solver can converge to a solution after relatively few iterations.
- Converging on an initial solution first can help you avoid initial instabilities that can
cause convergence problems later in the simulation. For example, when running with the
compressible flow solver, the initial solution can be critical. You can run some iterations
with the incompressible solver to generate results that you can use as approximated initial
conditions, and then run the compressible solver simulation using these imported initial
conditions.
- Importing initial conditions can make it easier to perform a parameterized simulation in
which you study the effects of changing a single variable. You can reduce the overall
computation time by starting each of the simulations from a previous converged
solution.
The results data that you import and the target simulation where you use them must reside in
the same location. Both simulations must be available locally or both must be on the cloud.