SBIR-STTR Award

Impulsive sources (landslides, explosions, and so forth) are capable producing extremely large waves in sufficiently deep water. If contained in a steep-walled ford-like channel, such waves can be propagated with little loss of energy over significant distances. The major energy dissipator in this case might be the occurrence of breaking in the narrow shallow zones along each bank; this loss mechanism can then be viewed as a damage mechanism precisely directed to shoreline facilities. Such a wave occurred in the famous case of Lituya Bay, Alaska in 1958. A landslide with energy comparable to a 100KT weapon generated an extreme wave system which caused devastating effects. Runup as high as 1700 feet denuded large forests; forests along the banks of the channel-like bay were stripped of trees to elevations of 200 feet. Similar effects could be expected in waterways of military and civil importance at many locations world wide, caused either by landslide or submerged explosion. Work conducted during the past two decades in the areas of explosion wave effects, landslides, and edge waves permit the significance of such channelized waves and the state of relevant knowledge to be assessed.

Phase I revealed that long explosion waves in channels such as hood canal may experience amplifications in height at the banks of a factor of two or more. This behavior greatly strengthens the damage potential of explosion generated water waves which may propagate for great distances in channels with little attenuation. An extremely destructive breaking zone might sweep the channel banks for a distance of many miles following detonation of a device of moderate yield. This behavior has been observed in nature after a landslide (energy comparable to 100 kt) produced edge bores which swept trees to 200 foot elevation for a length of several miles. Phase I presented semi-quantitative estimates using preliminary theories. work is proposed to establish wave profiles, velocities, accelerations, and breaking characteristics. The proposed work includes analytical, numerical, and experimental efforts (experiments to be performed by other dna contractors).

Keywords:
waves wave propagatio explosions landslides channels hydrodynamics safety vulnerability