In recent years, investigations show that the hazardous noise will be greatly reduced by replacing the large exhaust nozzle with a number of small nozzles, and quantitative relations were found.
The sound pressure level changes acutely in shock intersection, and shocks outside nozzle and exhaust plume cause strong noise.
声压级在相交激波点附近出现剧烈变化，喷管出口处的激波和排气羽流造成强噪声。
3
The standard deviation of four-nozzle impinging flame noise was greater than that of the two-nozzle impinging flame noise, but the change of the standard deviation was the reverse.