Tidal generation of internal waves from a periodic array of steep ridges

The generation of internal gravity waves by an oscillatory tidal flow over a periodic array of thin vertical walls is calculated analytically. For small values of the non-dimensional height B=2π H\!N/Lω , the radiated power per wall is the same as for a single thin wall, and proportional to B² , in agreement with the linear scaling. (Here H is the wall height, N the buoyancy frequency, L the wall spacing, and ω the tidal frequency.) The radiated power is periodic in B with period 2π . It diverges logarithmically for B=(1+2n)π , and vanishes for B=2nπ .