prędkość grupowa

In deep water this group velocity is proportional to the wave period.

The group velocity is depicted by the red lines (marked B) in the two figures above.

This distortion is directly related to group velocity, as follows.

Therefore, negative values of the group velocity will occur in these areas.

Reversal of group velocity was explicitly announced in the related published paper.

However, the wave's group velocity (associated with the energy flux) can be in any direction.

In deep water the groups travel at a group velocity which is half of the phase speed.

Recently, it has become possible to create gases in which the group velocity is not only larger than the speed of light, but even negative.

The group velocity itself is usually a function of the wave's frequency.

This is the same formula as the group velocity of a wave.