DRDO Anti-Radiation Missile by the Indian government In February 2016, it was reported that captive flight trials of anti-radiation missile are planned for April–May this year, and the maiden flight test by year–end by the missile technologists of the DRDO. According to DRDO sources, scientists will evaluate the performance of the seeker, navigation and control system, structural capability and aerodynamic vibrations during the captive flight trials. These will be followed by ground testing and the missile will be fired from Sukhoi Su-30MKI during the actual flight trial by year-end. The missile will be inducted in about two years after conducting a number of
Speed of sound km) can produce refraction equal to a typical temperature lapse rate of . Higher values of wind gradient will refract sound downward toward the surface in the downwind direction, eliminating the acoustic shadow on the downwind side. This will increase the audibility of sounds downwind. This downwind refraction effect occurs because there is a wind gradient; the sound is not being carried along by the wind. For sound propagation, the exponential variation of wind speed with height can be defined as follows: where In the 1862 American Civil War Battle of Iuka, an acoustic shadow, believed to have been enhanced