Wave friction refers to the resistance encountered or force exerted by water waves as they interact with the seabed or other boundaries. This interaction creates a frictional force that influences the dynamics of both the waves and the boundary layer near the bottom.
One key aspect of understanding wave friction, particularly in marine and lacustrine (lake) environments, is the concept of bed shear stress induced by waves. This force, exerted by the moving water on the bed surface, is crucial for processes like sediment transport.
The Wave Friction Factor (fw)
To quantify wave-induced bed shear stress, scientists and engineers use a critical dimensionless parameter called the wave friction factor (fw).
Based on the provided reference, the wave friction factor fw is an important dimensionless parameter used to estimate wave-induced bed shear stress.
Here's why the wave friction factor is significant:
- Estimation of Bed Shear Stress: It is directly used in calculations to determine how much force the waves are applying to the seabed.
- Control of Sediment Transport: Together with current-induced bed shear stress, wave-induced bed shear stress (estimated using fw) controls sediment transport in the marine and lacustrine environment. This means understanding fw is vital for studying erosion, deposition, and the movement of sand, mud, and other particles on the bottom.
- Modeling: It is a necessary input for models predicting sediment transport, coastal morphology changes, and bed stability under wave action.
However, the accurate determination of the wave friction factor can be challenging, as existing equations for estimating fw can sometimes either overestimate or underestimate its actual value in different conditions. This highlights the complexity and ongoing research into precisely quantifying wave friction and its effects.
In essence, wave friction is the physical phenomenon, and the wave friction factor (fw) is the dimensionless number used to measure its intensity in relation to wave-induced forces on the seabed, which in turn drives sediment movement.
