Please advice - How to fend off a dog?

Again and again, I am in a public reserve or on a walkway and I encounter irresposible dog owners: Dog is not on a leash and owner unable to controll the dog.

Dog runs at me and jumps me. I get dirty/wet and sometimes the pawns even damage my clothes. Most of all, I a scared that the dog will bite me.

Usually the stupid people tell me that their dog "just wants to play".

I don't care! I just want to walk or jog in peace.

QUESTION What can I do to disencourage the dog to approach me?

Yell at the dog? Make myself tall? A loud whistle?

I appreciate that it is just an animal and don't want to harm the dog - but I want to keep myself safe.