啪噠

啪哒
pādā
  1. (onom.) sound of object falling into water
  2. plop

CEDICT

onomatopoeic

Entry Composition

1 啪 pā
  1. (onom.) bang
  2. pop
  3. pow
2 噠 dā
  1. (phonetic)
  2. command to a horse
  3. clatter (of horses' hoofs)