In SharePoint we can clear the object cache from Site Collection Administration - Site collection object cache
Is there a way to do the same programmatically?
I know Serge van den Oever have found a way to do this (in SP2007), but since some of the classes and methods you need to call are internal, you need to use reflection to get it working.
NB: The publishing framework have been reworked alot in SP2010, so it might have changed alot.
A quick look in the API only gave this: http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.publishing.publishingcache.flushblobcache.aspx
So its likely that this is still internal methods
There was one suggestion posted to stackoverflow forum http://stackoverflow.com/questions/3046576/how-to-flush-object-cache-in-sharepoint-programmatically