Mach wave
From Academic Kids
A Mach wave (aka Mach front, Mach stem, Mach stem effect) is the constructive interference between a wave or pulsefront and its reflection, especially at a low incidence angle.
High-energy blast bombs (thermobaric, MOAB, nuclear, as opposed somewhat to neutron) can utilise the Mach wave to extend their blast-effect radius about half by judicious choice of detonation altitude.[1] (http://www.fas.org/man/dod-101/navy/docs/fun/part13.htm)[2] (http://131.122.80.20/wse/academic/courses/es300/lessons/lsn23teach.htm)
The Mach wave comes up in coastal engineering as a seawall-hugging surge much higher than impinging waves[3] (http://coast.geog.uu.nl/glossary.htm) or as an amplifier of scouring.
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