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High-resolution, time-accurate computational fluid dynamics validation of a 9.34 ft, four-blade, Mach-scaled S-76 rotor in hover is performed using the U.S. Department of Defense Computational Research and Engineering Acquisition Tools and Environments–Air Vehicles Helios software. The effect of blade tip shape variation is studied for three tip shapes: rectangular, swept tapered, and swept tapered anhedral. The effect of tip Mach number is studied for the swept-tapered tip. Computed results include rotor performance, blade airloads, and tip-vortex strength and position. The performance predictions are compared against the test measurements and good agreement is obtained. Compared with the swept-tapered tip, the rectangular blade incurs compressibility losses near the tip. The addition of anhedral to the swept-tapered tip improves performance as a result of redistribution of thrust.
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