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dc.contributor.authorMoldrheim, Mads Skjerven
dc.date.accessioned2024-07-09T23:50:38Z
dc.date.available2024-07-09T23:50:38Z
dc.date.issued2024-06-03
dc.date.submitted2024-06-03T10:02:31Z
dc.identifierHTEK399 0 O ORD 2024 VÅR
dc.identifier.urihttps://hdl.handle.net/11250/3139542
dc.description.abstractPrevious studies on methods for measuring turbulence in the ocean using an acoustic Doppler current profiler (ADCP) are characterized by applying the methods to data sets in the post-processing stage. This thesis explores the theoretical framework and assesses existing methods for measuring turbulence with the aim of establishing a fundament for the integration of a method for measuring turbulence onto an ADCP. Turbulence can be characterized as chaotic velocity fluctuations within a velocity field. The structure function D(z, r) and the frequency spectrum S(f) are methods for measuring the spatial and temporal velocity fluctuations respectively. From them, the turbulent kinetic energy dissipation rate ε can be derived, either through a curve fit approach or by a method in which the structure function or frequency spectrum is compensated. A requirement for these methods is for the turbulence regarded to be on the inertial subrange, a range of turbulent length scales where the turbulence is isotropic. The results of this thesis show that the curve fit approach is successful in estimating ε for both the structure function and the frequency spectrum method. The results of the original compensated structure function method show that the approach incorporates the Doppler noise in the ε-estimate, resulting in significantly elevated values. However, utilizing an estimate of the Doppler noise from the curve fit approach demonstrates that the compensated structure function can be corrected. The compensated frequency spectrum method has not been successful in producing satisfactory results. In addition, a set of criteria has been established that can be used to ensure that the methods are applied to the inertial subrange, which is a requirement for the validity of the methods. These criteria are suitable for integration into an algorithm and allow for the application of the methods without human management.
dc.language.isoeng
dc.publisherThe University of Bergen
dc.rightsCopyright the Author. All rights reserved
dc.subjectTurbulence
dc.subjectADCP
dc.titleAssessment of turbulence measurement methods for ADCP integration
dc.typeMaster thesis
dc.date.updated2024-06-03T10:02:31Z
dc.rights.holderCopyright the Author. All rights reserved
dc.description.degreeMasteroppgave i havteknologi
dc.description.localcodeHTEK399
dc.description.localcode5MAMN-HTEK
dc.description.localcodeMAMN-HTEK
dc.subject.nus752999
fs.subjectcodeHTEK399
fs.unitcode12-24-0


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