Measuring shallow water waves with pressure sensors
Goncalo, Vitor Manuel Henriques
Thornton, Edward B.
Tucker, Steven P.
MetadataShow full item record
For two locations within the surf zone sea surface elevations were observed using a wave staff and a pressure sensor while simultaneously the two horizontal orthogonal components, u and v, of water particle velocity were measured. Surface elevations derived from pressure sensors are lower, mainly in the region of the crest, compared with the same surface elevations measured with wave gages. Pressure records are more smoothed than wave gage records, and the energy computed for waves measured with a pressure sensor is consistently smaller than for waves measured with a wave gage. Methods for converting pressure to surface elevation are given which include the non-linear velocity term (u2+v2) which is usually neglected in the Bernoulli equation. Two techniques are proposed to include this term: 1) flowmeters are used to measure u and v, and 2) the Bernoulli term is derived by determining the velocities by convolving the pressure records using a weighting function determined from shallow water theory. The first technique gave improvements on the order of 3.4% to 7.8% of the total variance of the wave gage spectrum, whereas the second technique gave improvements on the order of 3.1% to 9.7%. The improvements in both cases are approximately the same, with the second technique having the advantage of requiring only a pressure transducer.
Approved for public release; distribution is unlimited
Showing items related by title, author, creator and subject.
Shavit, Zeev (Monterey, California. Naval Postgraduate School, 1985-12); NPS67-85-012CRA new optical technique for measuring Sauter Mean Diameter changes of a fuel spray under an electrostatic field was checked, calibrated, and implemented. The optical technique is based on measuring scattered light at two ...
Hussein, Faisa T. (Monterey, California: Naval Postgraduate School, 2016-12);While the use of recuperators in gas turbine engines is quite favorable for increasing cycle efficiency, it is currently only feasible to apply this technology to land-based engines. Transferring this technology to aviation ...
Hsu, Yu-Chih. (Monterey California. Naval Postgraduate School, 2005-12);There has recently been growing interest in the use of acoustic particle velocity measurements for sonar system applications such as source localization. It is expected that acoustic particle velocity sensors or "vector" ...