5.1. INTRODUCTION TO MOVABLE-BED MODELS
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fects of waves and/or currents. They can also be used to study micro-scale
features of sediment transport at scales close to prototype scale.
Examples of two-dimensional movable-bed model studies that are of
potential use to coastal engineers include:
• Beach profile evolution
• Dune erosion
• Ripple development
• Scour at coastal structures
• Initial adjustment of beach fills
• Response of beach fills to storms
• Response of cobble beaches to wave action
• Bedform translation under unidirectional currents
Figure 6.1 shows a movable-bed beach profile model being conducted in a
two-dimensional wave flume at the Waterways Experiment Station (WES).
Three-dimensional movable-bed models are much rarer, due in part to
high costs associated with these models. Sediment transport in 3-d models
could involve various combinations of longshore transport, onshore/oflshore
transport, scour at structures, and shoaling of channels.
Examples of three-dimensional movable-bed model studies that might
be employed by coastal engineers include:
• Erosion of oil drilling sand islands
• Littoral drift induced by oblique wave approach
• Effects of coastal structures on adjacent shores
• Formation of sand spits
• Shoaling at entrance channels and harbors
• Three-dimensional ripple formation
• Scour holes in the vicinity of structures
Figure 6.2 shows a three-dimensional movable-bed model being used at
WES to study scour resulting from combined waves and currents.
Unfortunately, not all of the above problems can be adequately scaled
with our present knowledge of sediment transport similitude, and it is important that known limitations are understood by both the modeler and
the client (Kamphuis 1985).
Both fixed-bed and movable-bed physical models can be either sitespecific or generic in purpose. Site-specific models pertain to an actual
241
fects of waves and/or currents. They can also be used to study micro-scale
features of sediment transport at scales close to prototype scale.
Examples of two-dimensional movable-bed model studies that are of
potential use to coastal engineers include:
• Beach profile evolution
• Dune erosion
• Ripple development
• Scour at coastal structures
• Initial adjustment of beach fills
• Response of beach fills to storms
• Response of cobble beaches to wave action
• Bedform translation under unidirectional currents
Figure 6.1 shows a movable-bed beach profile model being conducted in a
two-dimensional wave flume at the Waterways Experiment Station (WES).
Three-dimensional movable-bed models are much rarer, due in part to
high costs associated with these models. Sediment transport in 3-d models
could involve various combinations of longshore transport, onshore/oflshore
transport, scour at structures, and shoaling of channels.
Examples of three-dimensional movable-bed model studies that might
be employed by coastal engineers include:
• Erosion of oil drilling sand islands
• Littoral drift induced by oblique wave approach
• Effects of coastal structures on adjacent shores
• Formation of sand spits
• Shoaling at entrance channels and harbors
• Three-dimensional ripple formation
• Scour holes in the vicinity of structures
Figure 6.2 shows a three-dimensional movable-bed model being used at
WES to study scour resulting from combined waves and currents.
Unfortunately, not all of the above problems can be adequately scaled
with our present knowledge of sediment transport similitude, and it is important that known limitations are understood by both the modeler and
the client (Kamphuis 1985).
Both fixed-bed and movable-bed physical models can be either sitespecific or generic in purpose. Site-specific models pertain to an actual