blowdown

noun blowdowns

1. countable, uncountable The removal of liquid and solid hydrocarbons from a refinery vessel by the use of pressure.
2. countable, uncountable Cooling fluid discharged from a plant at the end of its cycle.
3. countable, uncountable Uprooting, overtopping, or bole breakage of trees by the wind; windthrow and windsnap.
4. countable, uncountable The action of aerodynamic forces to tend to cause a deflected control surface to return to its neutral position, or prevent the surface from deflecting past a certain point. At higher airspeeds, the 737's maximum rudder deflection is limited by blowdown, helping to prevent flight-control inputs from overstressing the aircraft's vertical stabilizer.
5. countable, informal, uncountable An instance of blowing down with compressed air. Give these parts a blowdown with your air hose before you put them in the ultrasonic cleaning tank.