Engineering topics

Gutierrez, O. A.

Publications and source records attributed to Gutierrez, O. A..

27 records · Page 2

NASA NTRS1972

Noise generated by STOL core-jet thrust reversers.

This paper summarizes the results of an experimental investigation on the noise generated by target-type thrust reversers. The experimental data are normalized and scaled up to sizes suitable for reversing the core jets of a 45,400-kg augmentor-wing-type STOL airplane. The scaling calculatings yield perceived noise levels well above the 95-PNdB design goal for both sideline and flyover at 152.5 m. V-gutter and semicylindrical reversers were tested with a 5.24-cm-diameter circular nozzle, and a semicylindrical reverser was also tested with a 7.78-cm-diameter circular nozzle. Other test variables were the spacing between nozzle and reverser, reverser orientation, and nozzle pressure ratio. The thrust reversers, in addition to being noisier than the nozzle alone, also had a more uniform directivity.

Stone, J. R.↗

NASA NTRS1972

Preliminary experiments on the noise generated by target-type thrust reverser models

Experiments are reported on the noise generated by model V-gutter and semicylindrical target-type reversers with circular nozzles. Nozzles were 5.24 and 7.78 cm in diameter. Nozzle pressure ratio ranged from 1.25 to 1.72. The spacing between reversers and nozzle, as well as the reverser orientation, was also varied. More noise was generated with reversers than with the nozzle alone. The measured maximum overall sound pressure level varied with the sixth power of the nozzle exit velocity. Noise levels were more uniform in regard to directivity with reversers than with the nozzle alone. It is concluded that thrust reversers, can be a significant noise problem, especially for STOL aircraft using thrust reversers during approach.

Gutierrez, O. A.↗

NASA NTRS1972

Noise generated by STOL core-jet thrust reversers

An experimental investigation on the noise generated by target-type thrust reversers is discussed. The experimental data are normalized and scaled up to sizes suitable for reversing the core jets of a 100,000 lb augmentor-wing-type STOL airplane. The scaling calculations yield perceived noise levels well above the 95-PNdB design goal for both sideline and flyover at 500 ft. V-gutter and semicylindrical reversers were tested with a 5.24-cm-diameter circular nozzle, and a semicylindrical reverser was also tested with a 7.78-cm-diameter circular nozzle. The thrust reversers, in addition to being noisier than the nozzle alone, also had a more uniform directivity. The maximum overall sound pressure level and the effective sound power level both varied with sixth power of the nozzle jet velocity.

Stone, J. R.↗

NASA NTRS1970