As far as I know a round of applause isn’t that common immediately after a viva. Maybe if you have a group of friends and colleagues on hand, perhaps with a bottle of something sparkling, there’ll be a call to applaud you. Probably circumstances won’t make it happen for you, but that doesn’t mean you don’t deserve it.
We clap our hands when we’re happy. We clap our hands at the end of something good. We clap our hands to show others that we agree. We do it to show respect.
There are lots of reasons for you to get a round of applause. I hope you do!