Final answer:
The wave steepness parameter H/L increases due to wave height increases or wavelength decreases, leading to wave breakage when H/L > 1/7. Diffraction, explained by Huygens's principle, can change wave direction but does not directly relate to wave steepness. Breaking occurs when wave-height-to-wavelength ratios exceed the critical steepness ratio.
Step-by-step explanation:
The parameter H/L is known as the wave steepness parameter, where H is the wave height and L is the wavelength. This parameter increases when wave height increases or wavelength decreases. In the context of ocean waves approaching a shoreline or passing through a small opening such as a harbor entrance, there can be interactions that affect both H and L.
The breaking criteria for waves is typically when H/L exceeds 1/7. This is because as waves travel into shallower water, their velocity decreases due to the interaction with the sea floor, but their height may remain the same or even increase as the waves are compressed. Eventually, if the wave becomes too steep, it will break, usually when H/L is greater than the critical ratio of 1/7.
Diffraction is a process described by Huygens's principle, which demonstrates how wave fronts change when encountering openings or obstacles. This principle can also be applied to understand changes in wave characteristics, such as when ocean waves pass through a narrow opening and cause bending (diffraction) of the wave edges. However, diffraction alone does not directly relate to the increase of the wave steepness parameter, which is primarily affected by changes in-depth and wave interactions with the sea floor.
Therefore, while diffraction and Huygens's principle explain how waves bend and change direction, the breaking criteria involve the steepness of the waves that can lead to them breaking upon reach a steepness where H/L > 1/7.