FREQUENCY DEPENDENCES OF THE GROUP VELOCITY OF NORMAL MODES IN SEA WAVEGUIDE WITH A BOTTOM WITH A GRADIENT OF SOUND VELOCITY
In the seabed, due to the increase in geostatic pressure, significant gradients of physical and acoustic properties are observed. The article deduces a formula and presents the results of calculating the phase and group velocities of normal modes propagating in a waveguide of a shallow sea with a bottom with a density and sound speed gradient. The acoustic properties of marine sediments are taken for the case of a real seabed. It is shown that the frequency dependences of the group velocity have an oscillating character, and at a certain frequency the group velocity increases significantly.