rra rra It's the sound when cutting fabric Some synonyms, words or similar expressions can be piaf piaf, chorororojoj, traj traj
"Arr arr" is obviously not Spanish. Nor do I believe that you write as well in any language. It may be because the expression in English "rah-rah" used since to qualify someone's behavior affected up to as a synonym for lying or misrepresentation; but it can be anything, I'm guessing.