ABSTRACT
Ski jumps use special effects to dissipate energy when compared to hydraulic jump basins. A ski jump involves the effects of jet dispersion. At the extreme, a compact inflowing water jet may be dispersed into a spray of water drops that form a cloud and fall slowly back to the earth. Although such extreme action is not usual, the dispersion process may dissipate a significant portion of the total hydrodynamic energy. A jet in air is effected by both turbulence and shearing action. If the jet trajectory is long and the discharge small, the two effects may cause the jet to disintegrate almost completely before striking the water surface in the tailwater. Apart from the typical configuration with a straight spillway as approach channel, trajectory basins may also be designed with orifice jets from arch dams, and these are often combined with a surface overfall.
