# threshold velocity

## threshold velocity

[′thresh‚hōld və‚läs·əd·ē]
(geophysics)
The minimum velocity at which wind or water begins to move particles of soil, sand, or other material at a given place under specified conditions.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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He spent much time observing British soldiers shooting .303 service rifles and concluded that the threshold velocity of the recoiling gun that induced flinching in riflemen was about 16 fps.
where [bar.[omega]] (>0) denotes the threshold velocity that enables us to determine which one among the three submodels is active; its value should be optimized along with those of the other parameters in [mathematical expression not reproducible].
As the user exceeds the threshold velocity for the high reliability traffic type with unknown mobility pattern, the proposed scheme tends to be executed more frequently.
As seen, the maximum erosion rate is closely related to the fluid velocity where a threshold velocity as well as a threshold particle size can be identified below which erosion is negligible.
Below a certain "threshold velocity" they don't upset satisfactorily upon target impact.
Thus, for the ogive-nose projectile with CRH of 3, when the targets are aluminum, steel, and other metals, the threshold velocity for the constant resistance is at least 1300 m/s; when the targets are concrete, rock, and other brittle materials, if the velocity of the projectile is higher than 400 m/s or so, the damage number would be very large, and the penetration resistance would clearly depend on the projectile's velocity.
For an alternate method of determining your proper tempo run pace, please see How to Determine Your Lactate Threshold Velocity in this issue.
Age (yrs) 23.1 (3.1) Height (m) 1.75 (.07) Weight (Kg) 70.5 (8.8) V[O.sub.2max] (ml x [min.sup.-1][Kg.sup.-1]) 58.2 (8.3) vV[O.sub.2max] (Km x [h.sup.-1]) 16.7 (1.6) vLT1 (Km x [h.sup.-1]) 10.9 (1.5) vLT2 (Km x [h.sup.-1]) 14.3 (1.2) vA50 (Km x [h.sup.-1]) 12.6 (1.3) V[O.sub.2max] = maximum oxygen uptake; vV[O.sub.2max] = minimum velocity to achieve V[O.sub.2max]; vLL1 = aerobic threshold velocity; vLL2 = anaerobic threshold velocity; vA50= average velocity (vLL1 + vLL2/2).
This threshold velocity will become very important when putting everything together to choose your ammunition.
This threshold velocity is given by this empirical equation; (Oke & Hannel, 1970):
When [t.sub.1] = dt, the threshold velocity is reached when static effects yield to dynamic effects, and friction drops.
In this case, the local velocity would be reduced to the critical velocity (threshold velocity at which sediment will erode) for the sediment size after the equilibrium scour depth develops.

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