title: Description and characteristics of a ''wave follower'' system for energy exchange studies in the vicinity of an air-water interface.
abstract: This paper describes the design, construction, and testing of an electromechanical servomechanism capable of responding to the vertical displacements of a wavy air-water interface. The device is to be used to maintain various probes at a fixed distance above or below the moving interface in a large wind-wave tank. The measurements so obtained will help to elucidate the mechanisms of mass, momentum, and energy transfer between air and water in the presence of waves. The dynamical characteristics of the wave follower are given. For frequencies below 9 Hz, it possesses a linear reponse characterized below 5 Hz by a 7.4 ms time lag. This is the sum of two time lags, 4.9 and 2.5 ms, which correspond, respectively, to the servomechanism itself and to the capacitance-type wave height measurement system. The maximum position error is found to be +/-2 mm for typical wave amplification by wind studies (maximum wave height of about 6 cm).
authors.affiliation: Institut de Mecanique Statistique de la Turbulence, Laboratoire Associe au C.N.R.S, I2, Avenue du General Leclerc, I3003 Marseille, France.
authors.forename: S
authors.initials: S
authors.lastname: Baldy
authors.forename: A
authors.initials: A
authors.lastname: Ramamonjiarisoa
authors.forename: M
authors.initials: M
authors.lastname: Coantic