The generation of internal waves by the interaction of deep ocean flows with bottom topography is considered. The interaction of quasi‐steady currents with the bottom topography is found to produce an internal wave drag and associated momentum flux of roughly ½ dyn/cm2, which is comparable to the average wind stress on the ocean surface. The waves are probably dissipated by critical layer phenomena in the lowest kilometer or so of the ocean, the result being a wave‐induced vertical mixing coefficient of order 10 cm2/s in that portion of the water column. The interaction of the barotropic tide with the bottom topography is found to result in a flux of energy of order 1 erg/cm2 s into the internal tide, which may represent a nonnegligible sink of the tidal energy. This mechanism appears to be capable of supplying a significant portion of the observed internal wave energy in the ocean. The internal tide is probably dissipated by inherently nonlinear phenomena: spectral transport by weak interactions and, in the upper oceans, strong interactions manifested by localized instabilities resulting in isolated patches of turbulence.

The process of internal gravity wave generation by the simple harmonic flow (U=U0, cos ω0t) of a stably stratified fluid (Brunt–Väisälä frequencyN) over an obstacle is investigated in some detail. Attention is primarily directed to the behaviour of the solution in various limiting cases, and to estimating the flux of energy into the internal wave field. In general, waves are generated not only at the fundamental frequency ω0, but also at all of its harmonics. But, for values of ω0/Ngreater than about one half, the waves of fundamental frequency are dominant. For values of ω0/N, less than about one half, the quasi-static approximation, in which the problem is considered as a slowly-varying version of the classical lee wave problem, is found to provide a viable estimate for the wave field. The general solution is found to compare favourably with the limited available experimental data.

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An estimated 110 million landmines, mostly antipersonnel mines laid in over 60 countries, kill or maim over 26 000 people a year. One of the dilemmas for removing landmines is the amount of false alarms in a typical minefield. Broadband electromagnetic induction spectroscopy (EMIS) is a promising technology that can both detect and identify buried objects as landmines. By reducing the number of false alarms, this approach significantly reduces costs associated with landmine removal. Combining the EMIS technology and a broadband EMI sensor, the scientific phenomenology that has potential applications for identifying landmines, unexploded ordnance, and hidden weapons at security checkpoints can now be explored.