GC: n
CT: When the jet is properly directed, there is a strong cross flow at the nose that controls the direction of velocity of approach to the slot. With adequate cross velocity at the nose the jet is directed into the pool and the flow remains stable, if not adequate it could create an unstable flow condition that could disorient the fish and reduce migration speed.
S: EA – http://www.fba.org.uk/fedora/repository/ealit:3935/OBJ/20002571.pdf (last access: 2 December 2014)
N: 1. velocity (n): early 15c., from Latin velocitatem (nominative velocitas) “swiftness, speed,” from velox (genitive velocis) “swift, speedy, rapid, quick,” of uncertain origin, perhaps related to vehere “carry”, or from the same root as vigil.
of (prep): Old English of, unstressed form of æf (prep., adv.) “away, away from,” from Proto-Germanic af (cognates: Old Norse af, Old Frisian af, of “of,” Dutch af “off, down,” German ab “off, from, down”), from PIE apo- “off, away”.
approach (n): mid-15c., from approach (v.). Figurative sense of “means of handling a problem, etc.” is first attested 1905.
2. It is defined as the velocity with which the flow approaches/reaches the notch/weir before it flows past it. The velocity of approach for any horizontal element across the notch depends only on its depth below the free surface. In most of the cases such as flow over a notch/weir in the side of the reservoir, the velocity of approach may be neglected. But, for the notch/weir placed at the end of the narrow channel, the velocity of approach to the weir will be substantial and the head producing the flow will be increased by the kinetic energy of the approaching liquid.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=velocity&searchmode=none (last access: 7 December 2014); http://www.etymonline.com/index.php?allowed_in_frame=0&search=approach&searchmode=none (last access: 7 December 2014). 2. NPTEL
SYN: approach velocity
S: NMFS – http://www.westcoast.fisheries.noaa.gov/publications/hydropower/fish_screen_criteria_for_pumped_water_intakes.pdf (last access: 2 December 2014)
CR: reservoir
