In a fluid handling apparatus a bladed interrupter structure adapted for {TAIL ~ pointwise interruption} of {HEAD ~ the boundary layer} of a fluid flow at an apparatus surface or surfaces of the apparatus immediately adjacent to the interrupter structure, the said structure comprising: 
In a fluid handling apparatus a bladed interrupter structure adapted for { TAIL ~ pointwise interruption } of { HEAD ~ the boundary layer } of a fluid flow at an apparatus surface or surfaces of the apparatus immediately adjacent to the interrupter structure , the said structure comprising :
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