Is it ok to contact a supervisor for a position?

I'm trying to get a job in higher education. I've been applying to lots of different positions that I am qualified for, but nothing. I've contacted some directors of departments for positions I'm applying for in an effort to get noticed beyond the online application process, but I'm not sure if this is helping either as I haven't gotten a response from the two or three I've contacted.

Is it ok to contact people, or do those hiring find it annoying? Any other suggestions? I've met with the alumni director at my alma mater and that was helpful because he gave me some good tips. But I was given a leave replacement shortly after this and had to push back applying until recently.

Re: Is it ok to contact a supervisor for a position?

Yes, especially if you know them already.

This is how I got my current job.

HR for my company is a nightmare otherwise.