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The sound barrier or sonic barrier is the large increase in aerodynamic drag and other undesirable effects experienced by an aircraft or other object when it approaches the speed of sound. When aircraft first approached the speed of sound, these effects were seen as constituting a barrier, making faster speeds very difficult or impossible.
The sound of a sonic boom depends largely on the distance between the observer and the aircraft shape producing the sonic boom. A sonic boom is usually heard as a deep double "boom" as the aircraft is usually some distance away. The sound is much like that of mortar bombs, commonly used in firework displays. It is a common misconception that ...
Noise barriers have been built in the United States since the mid-twentieth century, when vehicular traffic burgeoned. I-680 in Milpitas, California was the first noise barrier. [1] In the late 1960s, analytic acoustical technology emerged to mathematically evaluate the efficacy of a noise barrier design adjacent to a specific roadway. By the ...
A 0.1% open area will reduce the transmission loss from 40 dB to 30 dB, which is typical of walls where caulking has not been applied effectively [26] Partitions that are inadequately sealed and contain back-to-back electrical boxes, untreated recessed lighting and unsealed pipes offer flanking paths for sound and significant leakage.
Whipcracking is the act of producing a cracking sound through the use of a whip. Used during livestock driving and horse riding, it has also become an art. A rhythmic whipcracking belongs to the traditional culture among various Germanic peoples of Bavaria (Goaßlschnalzen), various Alpine areas (Aperschnalzen), Austria, and Hungary (Ostorozás).
The Texas penal code specifies that “a noise is presumed to be unreasonable if the noise exceeds a decibel level of 85 after the person making the noise receives notice from a magistrate or ...
Based on the data given in Tables 11 and 12, it appears that the approach noise of the Concorde is somewhat higher than that for present day commercial aircraft. The takeoff noise is, for locations close the airport, considerably higher than present aircraft. Considerably higher, here, means more than an order of magnitude (10 db) louder.
The threshold of hearing is generally reported in reference to the RMS sound pressure of 20 micropascals, i.e. 0 dB SPL, corresponding to a sound intensity of 0.98 pW/m 2 at 1 atmosphere and 25 °C. [3] It is approximately the quietest sound a young human with undamaged hearing can detect at 1 kHz. [4]