### 5.5.1. Modeling Thin Surfaces: Overview

Conceptually, to create a thin surface:

1. Create your domains.

2. Define a domain interface. Physics definitions are set on the Additional Interface Models tab; the provided models are determined automatically from the geometry.

   Choose Conservative Interface Flux to define a thin surface that has physics operating between the two sides; if you choose that option, set the Interface Model as well.

3. When you click OK to create the domain interface, a pair of boundaries are created (`Domain Interface 1 Side 1` and `Domain Interface 1 Side 2`) under Simulation > Flow Analysis > <domain_name>.

Release 18.2 - © ANSYS, Inc. All rights reserved.