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An experimental study was conducted to measure the growth rates of mechanically generated surface water waves when subjected to a fully developed turbulent channel airflow. The study was designed to test the accuracy of the growth rates predicted by Miles's (1962b) theory. For a series of wave frequencies (from 2·04 to 6·04 Hz at 0·50 Hz increments) and centre-line wind velocities (0·20, 1·12 and 1·84 m/s) wave amplitudes were measured at three stations (2–21, 3–43 and 4·65 m) downwind from a wave generator. In addition, for centre-line velocities of 1–12 and 1·84 m/s, U* (the velocity at the outer edge of the viscous sublayer) and U1, (the shear velocity) were obtained from measured mean velocity and Reynolds stress profiles. The wave amplitude measurements at the wind velocity of 0·20 m/s provided attenuation rate estimates which agreed reasonably well with theoretical attenuation rates based on viscous effects both on the walls and in the bulk of the water. The amplitude measurements at the wind velocities of 1·12 and 1·84m/s provided growth rate estimates which were compared with theoretical growth rates (computed using the wave frequency, U1 and U* predicted by Miles's (1962b) theory. At 1·12m/s Miles's growth rateswere two to five times larger than those measured; at 1·84 m/s Miles's growth rates were about two times larger.

Intermittently during the winter, swell and associated breakers appear along a beach on the lee side of Aruba, an island lying off the coast of Venezuela in the Trade Winds. It has been hypothesized that 14‐ to 15‐sec waves, generated by winter storms off the mid‐Atlantic coast of North America, propagate southward to Mona Passage, where they are refracted. They then propagate across the Caribbean Sea toward Aruba, where they are refracted off the northwest tip of the island and arrive at the beach on the leeward coast. Measurements of swell off this beach were conducted during March 1969. Spectra and directions of travel were computed from these measurements, and probable swell generation areas were located. Reasonable agreement is found between swell periods and directions computed from field measurements and those deduced from wave ray patterns. All evidence obtained is consistent with the hypothesis of a North Atlantic generation area.

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