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CHAPTER 6. SEDIMENT TRANSPORT MODELS
6.1.1 Movable-Bed Modeling Philosophical Remarks
Understanding sediment transport in coastal regimes is a perplexing challenge that in all likelihood will continue to frustrate coastal researchers
and engineers for generations to come1. The hydraulic/sediment interaction is so complex that "... the older Einstein is said to have warned his
son strongly of the difficulties in dealing with sediment transport processes”
(Vollmers 1989). Thus, it should come as no surprise that “movable-bed
scale model investigations of coastal erosion and sediment transport are
probably the most difficult hydraulic models to conduct” (Hudson, et al.
1979).
1 Author’s own opinion on the subject.
Part of our motivation for attempting physical models of sediment transport processes was expressed by Kamphuis (1985), when he said,
Field work is often prohibitively expensive or impossible to perform because parameters are not readily manipulated. Numerical modeling is dependent on physical interactions which are
poorly understood and virtually impossible to formulate successfully in mathematical terms.
If we can conduct a movable-bed scale model in which we have corrected
for scale effects reasonably well, then we should expect a model response
similar to what might be expected in nature. This is a valuable study tool
for coastal engineers to have at their disposal.
Another reason for pursuing movable-bed models in the face of their
inherent difficulty was given by Le Méhauté (1976):
Experience in handling the scale models, particularly the movablebed models, permits us to think about solutions that may not
come to mind without their use. This develops sophistication
in our approach to problem solving and thus contributes to the
advancement of the state-of-the-art.
Hudson, et al. (1979) gave the basic philosophy for movable-bed scale
modeling as fully understanding the physical processes involved and ensuring that the relative magnitudes of all dominant processes are the same in
model and prototype. They also stated, “This is an impossible task for
movable-bed models ...” because of the complications of the fluid-sediment
interactions, and thus it is necessary to attempt to reproduce the dominant
process “... with the anticipation that other forces are small.”
Similar views are held by Dean (1985), who listed two major requirements for proper physical modeling of sand transport processes:
CHAPTER 6. SEDIMENT TRANSPORT MODELS
6.1.1 Movable-Bed Modeling Philosophical Remarks
Understanding sediment transport in coastal regimes is a perplexing challenge that in all likelihood will continue to frustrate coastal researchers
and engineers for generations to come1. The hydraulic/sediment interaction is so complex that "... the older Einstein is said to have warned his
son strongly of the difficulties in dealing with sediment transport processes”
(Vollmers 1989). Thus, it should come as no surprise that “movable-bed
scale model investigations of coastal erosion and sediment transport are
probably the most difficult hydraulic models to conduct” (Hudson, et al.
1979).
1 Author’s own opinion on the subject.
Part of our motivation for attempting physical models of sediment transport processes was expressed by Kamphuis (1985), when he said,
Field work is often prohibitively expensive or impossible to perform because parameters are not readily manipulated. Numerical modeling is dependent on physical interactions which are
poorly understood and virtually impossible to formulate successfully in mathematical terms.
If we can conduct a movable-bed scale model in which we have corrected
for scale effects reasonably well, then we should expect a model response
similar to what might be expected in nature. This is a valuable study tool
for coastal engineers to have at their disposal.
Another reason for pursuing movable-bed models in the face of their
inherent difficulty was given by Le Méhauté (1976):
Experience in handling the scale models, particularly the movablebed models, permits us to think about solutions that may not
come to mind without their use. This develops sophistication
in our approach to problem solving and thus contributes to the
advancement of the state-of-the-art.
Hudson, et al. (1979) gave the basic philosophy for movable-bed scale
modeling as fully understanding the physical processes involved and ensuring that the relative magnitudes of all dominant processes are the same in
model and prototype. They also stated, “This is an impossible task for
movable-bed models ...” because of the complications of the fluid-sediment
interactions, and thus it is necessary to attempt to reproduce the dominant
process “... with the anticipation that other forces are small.”
Similar views are held by Dean (1985), who listed two major requirements for proper physical modeling of sand transport processes: