The Default material database contains at least one instance of every material type. A convenient way to create a new material is to use a Default material as an example. Because these materials are read-only, use the Material Editor to copy the original into a custom database, and modify the copy.
A Resistance material definition does not reference specific Cartesian components. Instead, the values are saved as the Through-Flow, and the two Normal Components. The specific Cartesian orientation of the material is specified when a resistance material is applied to a part.
A thermal conductivity can also be assigned to a resistance material. This can be different from the surrounding fluid, and is important for heat transfer analyses in which the material will play a thermal role.
No other fluid property information is required to define a resistance. The Solver automatically applies the fluid property information from the surrounding fluid to the resistance. For this reason it is very important that a resistance region only contact one fluid material type. If, for example, a resistance contacts air on one side and water on the other, an error will result, and the analysis will not run.