In the UK, we usually say "rumbling"

Rumbling or growling. Rumbling is the sound of distant thunder, or an old-fashioned train approaching from the distance. Growling is a low, deep sound that a dog makes when it feels threatened. Both can be used for stomach noise.

Usually this sound is described as a growl, or the stomach is growling.

Don't describe the sound of your stomach. Just say: "I am hungry as wolf" :)

My stomach is always 'rumbling' as I am hungry all the time. The British would say 'rumbling', although there are many variants on this depending on where you are from.