Far‐Field Noise Effects from Static Tests of the Saturn Booster Free

The acoustic noise generated by the Saturn booster is characterized by the extremely large powers, broad directivity, low frequency power spectra, and low efficiency. Results obtained from a field survey of sound from the Saturn's initial series of static tests reveal some unique aspects of sound generated by clustered jet streams. Initial firings were of two and four engines each which produced acoustic powers of 0.56 and 1.6 megawatts, respectively. Corresponding acousthe efficiencies were quite low, being 0.03% for the two‐engine test and 0.04% for the four‐engine test. However, acoustic power radiated from eight‐engine tests ranged from 25 to 40 megawatts, with an acoustic efficiency near 0.5%. Spectra from all tests peaked between 10 and 100 cps, and were rather ragged, showing severe dips near 250 cps and minor peaks at 1000 and 6300 cps. Directivity was quite broad in the eight‐engine tests and much sharper in the two‐ and four‐engine firings. While it is desirable to isolate cluster effects on noise generation it is difficult to do so because of the complicated jet deflector used on the tests.