Excel Service data model refresh on open

In SharePoint 2013, I have a PowerPivot excel spreadsheet sitting in a gallery, and it's a dashboard that's underpinned by financial data. I want that model to refresh as the user opening the sheet (right back to the data source) so that the user only gets the data they're allowed to see, governed by the security in the tabular cube delivering the data. Is there anyway to force this? or alternatively how can I apply a secure model of finance data that provides only relevant user data, as prescribed by the tabular model?