Ripple

гребен

greben

(implement for removing the seeds from flax)

пулсация

pulsacija

(small oscillation of an otherwise steady signal)

ромон

romon

(sound similar to that of undulating water)

правя вълнички

pravja vǎlnički

(to move like the undulating surface of a body of water)

ромоля

romolja

(to make a sound as water running across shallows)