Temporal variation of vortex scour process around caisson piers.

The concept of conservation of power during scour by the primary vortex formed in front of caisson piers is used to develop a relation for the temporal of scour depth variation. To test this relation, experiments were conducted using two sediment beds, three types of caisson piers and four relative flow depths. The agreement between the temporal variation of scour depths from the present approach and the literature data is good. The computed values of other researchers also agree fairly with the present proportionality constants. An expression for scour duration to reach the equilibrium scour depth is deduced from the power concept based on long duration literature data. The validity of this expression is verified for the equilibrium duration concept. [ABSTRACT FROM PUBLISHER]