IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
artículos
Título:
NEW FORMULATION FOR EROSION OF NEWLY DEPOSITED COHESIVE BEDS BY UNIDIRECTIONAL CURRENTS
Revista:
OCEAN DYNAMICS
Editorial:
SPRINGER HEIDELBERG
Referencias:
Año: 2010 p. 1 - 16
ISSN:
1616-7341
Resumen:
Experiments recently carried out on kaolinite showed that cohesive bed erodibility was controlled by the magnitude of pre-threshold currents effect that was minimized by using a 2 mm bed thickness. However,  it was observed that the equilibrium condition e = ef ¡Ö 0 in which is based the conventional methodology to measure the erodibility of a newly deposited cohesive bed does not occur and that erosion appear to continue regardless of eroded depth.  By the result from 140 experiments, the relationship to - e for different bed depths was obtained in the form ln(e) = a to + b, where a decreases with depth following an inverse relationship with b, leading to a general equation which is almost identical to that employed by the conventional methodology. However, such formulation conceptually differs in that for a sediment bed homogeneous in grain size and mineralogy tb remains constant with depth, whilst  a is variable and would depend mainly on the sediment density. Thus, it is demonstrated by an independent way that the conventional methodology that has been employed on newly deposited cohesive sediments erosion during more than 20 years may in such cases have had a misinterpretation. According to the new formulation proposed here, an easy to built instrument and an adequate methodology to measure cohesive sediment erodibility as well as the influence of chemicals and biology on it, is designed. This investigation reopens a basic research line that long time ago seemed to be concluded and that shows multiple uses in applied research.