Comparative evidence

h₃reu̯h₁, h₃reu̯h₂, h₃reu̯h₃

• OInd. ru- 'sound', 'noise'; 'fear', 'alarm'; 'war', 'battle' (MW: 881)

• OInd. ru- 'cry' (Whitney 1885: 141); 'roar', 'bellow', 'howl', 'yelp', 'cry aloud'; 'make noise, 'make sound', 'sing' (as birds), 'hum' (as bees); 'praise' (MW: 881)

References

MW = Monier-Williams, M. 1899. A Sanskrit-English Dictionary. Clarendon Press.
Whitney 1885 = Whitney W. D. 1885. The roots, verb forms and primary derivatives of the Sanskrit language. A supplement to his Sanskrit grammar. Leipzig.