This paper presents experience from the use of an Acoustic Doppler Velocity Profiler in the surf zone over a large-scale experimental barred beach. In the first part of the paper, attention is focused on the description of a proper ADVP set-up and on the determination of relationships for the horizontal and vertical velocity components valid for the oscillatory flow case. In the second part, horizontal velocity component data from the ADVP are compared to the pre-processed measurements from two other velocity measuring devices for breaking waves, as well as near the end of the surf zone. As expected, in the outer region of the surf zone velocity measurements appear influenced by air entrainment. In the bore-like region where the effects of wave breaking are less intense and where the wave is reforming, the horizontal velocity is in reasonable agreement with the rest of the measurements. Although the ADVP appears much noisier than other instruments, the role of bubbles in outer zone is prevalent in its measuring error and gives a large underestimation. Furthermore, for the adopted experimental conditions, the analysis shows that the use in the bore-like region of relationships for the horizontal velocity component that are valid for a uniform flow generates a negligible error.
Capabilities and limits for ADVP measurements at breaking waves and bores
TOMASICCHIO, Giuseppe
2006-01-01
Abstract
This paper presents experience from the use of an Acoustic Doppler Velocity Profiler in the surf zone over a large-scale experimental barred beach. In the first part of the paper, attention is focused on the description of a proper ADVP set-up and on the determination of relationships for the horizontal and vertical velocity components valid for the oscillatory flow case. In the second part, horizontal velocity component data from the ADVP are compared to the pre-processed measurements from two other velocity measuring devices for breaking waves, as well as near the end of the surf zone. As expected, in the outer region of the surf zone velocity measurements appear influenced by air entrainment. In the bore-like region where the effects of wave breaking are less intense and where the wave is reforming, the horizontal velocity is in reasonable agreement with the rest of the measurements. Although the ADVP appears much noisier than other instruments, the role of bubbles in outer zone is prevalent in its measuring error and gives a large underestimation. Furthermore, for the adopted experimental conditions, the analysis shows that the use in the bore-like region of relationships for the horizontal velocity component that are valid for a uniform flow generates a negligible error.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
