Optimization of the hybrid ship transport factor through retrofitted wave cancelling side-hull expansions and bow bulb

The US Navy is currently considering the introduction of a Flight III variant beginning with DDG-123 in Fiscal Year 2016. The new design incorporates a new combat system and associated power and cooling upgrades. The overall system improvements increase the payload of the ship and the resulting increased displacement has a negative impact on the service life allowance for range, fuel consumption and sea-keeping characteristics. The present objective is to increase the hull displacement without resistance and sea-keeping penalty and with minimal modifications to the baseline DTMB-5415 design (open literature surrogate of the existing DDG-51 hull form) by using retrofitted blisters in the form of side hull expansions and a bow-bulb. The investigation makes use of high-performance CFD computing for analysis of wave cancellation mechanisms. A candidate modified 5415 design with both blisters and bow bulb shows a resistance reduction of ~11% w.r.t. the baseline 5415 in the design speed range of 15-19 knots, even though the displacement is increased by 8%, such that the transport factor is increased by 19%.