Tidal Characteristic Numbers of Bed Load Transport: Difference between revisions
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===Tidal Cycle=== | ===Tidal Cycle=== | ||
====Residual Bed Load Transport during a Tidal Cycle | ====Residual Bed Load Transport during a Tidal Cycle==== | ||
Residual amount of bed load material which is transported by means of ebb and flood currents through a cross section (the different transport directions are taken into account). If the transport by means of flood current is equal but in opposite direction of the ebb current transport this will result in a zero advective residual transport of bed load material. | Residual amount of bed load material which is transported by means of ebb and flood currents through a cross section (the different transport directions are taken into account). If the transport by means of flood current is equal but in opposite direction of the ebb current transport this will result in a zero advective residual transport of bed load material. | ||
====Bed Load Lransport, Flood-Ebb-Ratio | ====Bed Load Lransport, Flood-Ebb-Ratio==== | ||
flood to ebb ratio for the different amounts of bed load material which are transported by means of flood and ebb currents | flood to ebb ratio for the different amounts of bed load material which are transported by means of flood and ebb currents | ||
Revision as of 09:19, 9 June 2010
Graphical representation of characteristic numbers of bedload transport (with German text only). This graphical representation is also available in Encapsulated PostScript format
Motivation
The calculation as well as the graphic visualization of various tidal characteristic numbers of bed load transport contributes to an improved understanding of tidally dominated transport processes in estuaries. Spatial variations of bed load transport by means of flood and ebb currents can be highlighted for areas like coastal seas and estuaries.
- The calculated characteristic numbers of bed load transport do allow for a separation between the amount of bed load material transported by means of the flood current as well as by means of the ebb current. Differences in between the two transport rates are mainly due to different hydrodynamic regimes during ebb and flood tide (e.g. maximum and/or mean current velocity, duration of ebb/flood current).
- The asymmetry between ebb and flood current transport can be at best demonstrated using the ratio between flood- and ebb-induced transport rates. But also the calculated residual transport is a good measure for these differences. Zones of convergent or divergent residual transport indicate depositional or erosional areas, whereas zones with a mostly homogeneous residual bed load transport rate are related to a dynamically stable bed.
An automatic analysis of all tidal characteristic numbers of bed load transport is carried through by the computer program TDKLF.
Definitions for the Tidal Characteristic Numbers of Bed Load Transport
Flood Current
Bed Load Transport due to Flood Current
Amount of Bed Load Material which is transported by means of flood current through a cross section
Ebb Current
Bed Load Transport due to Ebb Current
Amount of Bed Load Material which is transported by means of Ebb Current through a cross section
Tidal Cycle
Residual Bed Load Transport during a Tidal Cycle
Residual amount of bed load material which is transported by means of ebb and flood currents through a cross section (the different transport directions are taken into account). If the transport by means of flood current is equal but in opposite direction of the ebb current transport this will result in a zero advective residual transport of bed load material.
Bed Load Lransport, Flood-Ebb-Ratio
flood to ebb ratio for the different amounts of bed load material which are transported by means of flood and ebb currents
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