a state of violent disturbance and disorder (as in politics or social conditions generally); "the industrial revolution was a period of great turbulence"
a mechanism consisting of a metal honeycomb through which hot fluids circulate; heat is transferred from the fluid through the honeycomb to the airstream that is created either by the motion of the vehicle or by a fan
heater consisting of a series of pipes for circulating steam or hot water to heat rooms or buildings