Let’s say a ninety-thousand hp 2 -stroke engine with four turbochargers is driving a container vessel 320 mtrs. long and 46 mtrs. wide with a draft of 14,5 mtrs. in heavy seas.
If the Captain is a cautious man he instructs his mates to adjust accordingly, especially the second mate in dog watch 00-04 am. If not, it might happen that the propeller is emerging and the fuel racks are abruptly retracted by the governor of the main engine. The engine revolution is reduced remarkably and the surplus of air from the turbochargers doesn’t know where to go - it flows back through the suction strainers of the chargers, giving a barking or coughing or whining - however you want to name it - noise. Latest then the C/E is on the bridge and shouting to the poor 2nd. mate to reduce revolutions. I have never seen recirculating valves because cautious seamen avoid situations like that and why invest money to prevent it ?
But you are right, there might be situations on vessels where this is necessary.