It is a sudden large increase in aerodynamic drag that occurs as the speed of an aircraft approaches the speed of sound.
Definition of SOUND BARRIER. : a sudden large increase in aerodynamic drag that occurs as the speed of an aircraft approaches the speed of sound. See sound barrier defined for English-language learners. See sound barrier defined for kids. ADVERTISEMENT U.S. Navy F/A-18 within the sound barrier. The white cloud formed by decreased air pressure and temperature around the tail of the aircraft (see Prandtl-Glauert Singularity). By the 1950s many combat aircraft could routinely break the sound barrier in level flight, although they often suffered from control problems when doing so, such as Mach tuck. Modern aircraft can transit the barrier without it even being noticeable. Mass Loaded Vinyl is a limp-mass material sound barrier made of high-temperature fused vinyl and no lead fillers. The vinyl sound barrier reduces airborne sound transmission through walls, floors and ceilings. It comes in rolls 54 wide, weighs 1 lb./ sq. ft. and has an STC 27. Sound Barriers. Sound barriers are materials used to block or soundproof a room or piece of noisy equipment. We have various types of sound blocking systems, enclosures and materials for existing and new soundproofing construction. Historically, this was referred to as breaking the sound barrier. The passage from subsonic to supersonic speeds is accompanied by some unusual phenomena which lie in the realm of nonlinear mechanical events-events involving some degree of chaos.  Noise barrier walls made of absorptive material mitigate sound differently than those that are a hard surface. A sound reducing barrier wall with a porous surface material and sound-dampening content material is said to be absorptive. Noise barrier earth berm along California State Route 12, Sonoma County, California. Some noise barriers consist of a masonry wall or earthwork, or a combination thereof (such as a wall atop an earth berm). If the object has sufficient acceleration, it can burst through this barrier of sound waves and move ahead of the radiated sound. The change in pressure as the object outruns all the pressure and sound waves in front of it is heard on the ground as an explosion, or sonic boom. Then, just as the aircraft bursts through the sound barrier, the air is locally disturbed by the resulting shock wave and the condensation/vapor cloud disappears. Ensign Gay snapped his photo at the moment he heard the boom, just before the cloud vanished. Ad. The original issue leading to the concept of a sound barrier is a result of propeller technology. As an aircraft approaches the speed of sound, the movement of the propeller becomes disruptive to sound waves, causing turbulence and reducing the performance of the aircraft. Top 10 amazing movie makeup transformations. Sound travels as a wave through mediums such as air, liquid and plasma. In the air, the speed that the waves travel is determined by atmospheric conditions, so the speed of sound can vary depending on temperature. A noise barrier (also called a soundwall, sound berm, sound barrier, or acoustical barrier) is an exterior structure designed to protect inhabitants of sensitive land use areas from noise pollution. Noise barrier earth berm along California State Route 12, Sonoma County, California. Some noise barriers consist of a masonry wall or earthwork, or a combination thereof (such as a wall atop an earth berm). subsonic: A vehicle that is traveling slower than the speed of sound (M. supersonic: sound barrier: The term sound barrier is often associated with supersonic flight. In particular, breaking the sound barrier is the process of accelerating through Mach 1 and going from subsonic to supersonic speeds. Basic Definitions: speed of sound: The speed of sound is a basic property of the atmosphere that changes with temperature. For a given set of conditions, the speed of sound defines the velocity at which sound waves travel through a substance, such as air.
http://www.merriam-webster.com/dictionary/sound%20barrier https://en.wikipedia.org/wiki/Sound_barrier https://acousticalsolutions.com/product-category/sound-barriers/ http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/soubar.html https://en.wikipedia.org/wiki/Noise_barrier http://www.scientificamerican.com/article/what-happens-when-an-airc/ http://www.wisegeek.com/what-is-the-sound-barrier.htm https://en.wikipedia.org/wiki/Noise_barrier http://www.aerospaceweb.org/question/atmosphere/q0126.shtml
what is a sound barrier