Joint High Speed Sealift (JHSS) Baseline Shaft & Strut (BSS) Model 5653-3: Series 2, Propeller Disk LDV Wake Survey; and Series 3, Stock Propeller Powering and Stern Flap Evaluation Experiments

Model 5653-3, scale ratio 34.121, is representative of the Joint High Speed Sealift (JHSS) conventional Baseline Shaft & Strut (BSS) hullform with Gooseneck Bulb (GB). This report documents the Propeller Disk LDV Wake Survey tests (Series 2) and Stock Propeller Powering and Stern Flap Evaluation tests (Series 3. In order to assist in the design of a propeller for the BSS hull, the nominal wakes in the inboard and outboard starboard propeller planes were measured using LDV. The velocity fields were used to determine the average flow near the propeller tip in the event that ducted propellers or podded propulsors were to be designed for this hull. Harmonic content of nominal wake was calculated up to the 16th harmonic for both inner and outer shafts. The stock propeller powering prediction for the JHSS BSS GB configuration with stern flap installed, with SAD included, no power margin, non-cavitating propellers, at design (DES) displacement, indicates that at the 36 knot speed of interest the total delivered power required will be 149,440 hP (111,440 kw), and to attain the desired speed of 39 knots will require 218,180 hP (162,690 kw). This 39 knot speed is achievable within the expected total installed power for the JHSS BSS. The selected stern flap design for the JHSS BSS has full-scale dimensions of chord length 12.8ft (3.9m) equivalent to 1.35% LWL, span 52.9ft (16m) representing 80% of the maximum span, and an angle of 100 trailing edge down relative to the local buttock slope at the centerline of the transom. At DES displacement, the stern flap exhibited a reduction in required delivered power of 7.6% at the 36 knot optimization speed, and a reduction in propeller speed of 2.9 RPM. The original document contains color images. All DTIC reproductions will be in black and white.