Two-dimensional structure of flow at a confluence of channels, Bahía Blanca Estuary, Argentina.

PIERINI, JORGE O; CARBONE, M ELIZABETH; MARINI, M FABIAN; PERILLO, GERARDO M. E.

Mar del Plata

Congreso; Joint IAPSO-IABO Assemblies, 2001: An Ocean Odyssey; 2001

IAPSO-IABO

This paper presents two-dimensional data of mean and sediment flow collected at a naturalconfluence of channels to describe the two-dimensional flow field to assess the role of changes inbed morphology occurring during transport-effective events on the structure of flow at a confluence;and to examine how the two-dimensional structure of flow varies with changes in the ratio ofmomentum flux. At each station, vertical profiles of velocity, salinity, temperature and suspendedsediment were obtained. The mean field of flow is characterized by the acceleration of flow in thedownstream portion of the post-confluence channel; a stagnation zone at the apex of the junction; azone of flow deviation and strong fluid close to the margin of the tributary mouth; and reducedvelocities over the opposite margin. The position and extent of these zones vary with changes in theratio of momentum flux over the whole tidal cycle. The effect of the junction produces a distortion ofthe vertical profile flow and in the suspended sediment transport.