Measurements of the vertical acceleration in wind waves.

Abstract

Recent theoretical studies of the accelerations in regular gravity waves of finite steepness have shown striking differences between the Eulerian and the Lagrangian accelerations (those measured by fixed instruments or freely floating instruments, respectively). Attention is directed to field observations of accelerations in random seas. Two sets of data were analyzed, representing Eulerian and Lagrangian measurements. The Eulerian accelerations were found to be notably asymmetric, with maximum downwards accelerations exceeding 1.6 g. The Lagrangian acceleration histograms are narrower and more symmetric, in general. The acceleration variance is highly sensitive to the high frequency cut off in both types of data. (from authors' abstract)