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# Are there default environmental properties present when running a simulation?

## Question:

Are there any default environmental properties already defined in the simulation space?

Are we simulating in a vacuum or are there air or fluid properties already present?

## Applies to:

* Simulation

## Answer:

Unless you define a boundary condition explicitly, we assume that the model is isolated from its surrounding environment. Meaning no interactions whatsoever. If you want a more realistic approach you can define an ambient temperature and use a convection boundary condition on all faces of the model.

## Keywords:

*boundary property properties question fluid condition environmental air vacuum*