What is wave refraction?

Wave refraction is the bending of waves as they pass from one medium to another.

When waves encounter a change in the medium they are travelling through, such as from deep water to shallow water, their speed changes. This causes the waves to bend, or refract, towards the normal (an imaginary line perpendicular to the surface of the new medium). The amount of bending depends on the angle of incidence, or the angle at which the wave approaches the boundary between the two media.

In the case of waves approaching a coastline, refraction can cause the waves to bend around headlands and into bays. This can create areas of calm water in the bays, while the headlands experience more intense wave action. Refraction can also cause waves to converge or diverge, depending on the shape of the coastline.

Wave refraction has important implications for coastal engineering and management. Understanding how waves will behave as they approach a coastline can help engineers design structures such as breakwaters and jetties to protect shorelines from erosion and flooding. It can also inform decisions about where to locate coastal developments and infrastructure, such as ports and marinas.