Abstract
AbstractCurrently, the sedimentation process concerning the formation of the morphological changes of deltas under the action of waves has received little attention. Two numerical simulations were carried out in this study to explore the sedimentary morphological changes of deltas under wave action. In the first experiment, the morphological characteristics of river-dominated deltas and wave-dominated deltas were compared. Results showed that a wave-dominated delta was more likely to produce slender and stable rivers relative to a river-dominated delta. In the second experiment, the morphologies of wave-dominated deltas with sediments of different grain sizes were compared. Results indicated that delta morphology was not significantly correlated with the median grain size (ϕ50{\phi }_{50}) of the sediment, and the average grain size of the coarser sediments (ϕ25{\phi }_{25}) was an important factor affecting delta morphology. Moreover, a delta with a largerϕ25{\phi }_{25}value of the input sediment, a smaller topset gradient, and a smaller number of active river channels had a more arcuate shape. The results showed that the hydrodynamic numerical simulation method has the ability to reveal the evolution of deltas under the action of waves. The final simulation results were consistent with the actual delta data.
Highlights
Currently, the sedimentation process concerning the formation of the morphological changes of deltas under the action of waves has received little attention
When all three parameters of delta morphology became stable, the delta had entered a stable state, and the time when the steady state appeared was at about two thirds of the total simulation time (Figure 5)
The results showed that the area of the river channels without wave action increased more significantly over time than the area of the river channels with wave action
Summary
Abstract: Currently, the sedimentation process concerning the formation of the morphological changes of deltas under the action of waves has received little attention. Two numerical simulations were carried out in this study to explore the sedimentary morphological changes of deltas under wave action. The morphological characteristics of river-dominated deltas and wavedominated deltas were compared. Results showed that a wave-dominated delta was more likely to produce slender and stable rivers relative to a river-dominated delta. The morphologies of wave-dominated deltas with sediments of different grain sizes were compared. A delta with a larger φ25 value of the input sediment, a smaller topset gradient, and a smaller number of active river channels had a more arcuate shape. The results showed that the hydrodynamic numerical simulation method has the ability to reveal the evolution of deltas under the action of waves. The final simulation results were consistent with the actual delta data
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