There are a couple of options to refresh the cache....
Option 1: Show most recent data for all views.
To show the most recent data for all Tableau Server views, change the cache settings to Balanced or Refresh more often.
- On the computer running Tableau Server, navigate to the following location: Start menu > All Programs > Tableau Server > Configure Tableau Server.
- On the Data Connections tab, select Balanced or Refresh more often.
Option 2: Show the most recent data for a specific view.
To show the most recent data on specific views, use one of the following options:
- Open the view, and then click Refresh Data.
- Append ?:refresh=y to URL of the view. For example: http://servername/views/workbookname/dasbhoard1?:refresh=y
The ability to set more granular cache settings is not built into the product.
However if you would like to up-vote this Idea in the Community, please check out the following link...
Hope this helps