From the looks of this article in the SOLIDWORKS Knowledge Base you would not be able to import a mesh into SOLIDWORKS/Simulation from another source:
Solution Article ID: S-017202
Question: Can SOLIDWORKS® Simulation import mesh and results data from other CAE system?
Answer: Regarding mesh data, it is not possible to import mesh data generated in other CAE systems into SOLIDWORKS® Simulation.
It is not the best news but it is an answer.