You write sizzle.
baaah
squeak
BOOM!
bacock
You could write Bzzzz or Zzzz or any other buzzing sort of sound.
The sound a whistle makes is often described as "whoo" or "wee" depending on the pitch and intensity of the sound.
"bzzftt"
dribble dribble
BWAAAAAAAAAAAAAAAAAAAAAAAAA~!!! At least that's the sound he makes around here.
sonar is used, to steer a vessel because sound waves are emitted around the vessel. Then the sound waves are traveled back to the vessel. If the sound waves are block by an object, it will tell the vessel.
whoo ooh whoo ooh