vtme

Hi everyone, After being admitted to a masters/Ph.D program, can you request to have an advisor outside of the department to which you have been admitted? For example, I applied to several schools into the mechanical engineering program focusing on computational fluid dynamics, but i was recommended by my undergrad adviser to try and work with a specific professor in the Engineering Sciences and Mechanics department who pretty much does a ton of CFD. So my question is if i am enrolled into the ME program, do i HAVE to have an adviser who is listed under the ME department? Thanks