Front Cover
 Title Page
 Table of Contents
 List of Tables
 List of Figures
 List of symbols
 Previous work
 Multiple transducer array
 Field measurements of bedforms...
 Observations of bedform dynami...
 Discussion and conclusions
 Appendix A: SIS95 and SIS96 data...
 Appendix B: SIS95 and SIS96 programs...
 Biographical sketch

Group Title: UFL/COEL-TR ;, 115
Title: Wave generated bedforms in the near-shore sand environment
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00075478/00001
 Material Information
Title: Wave generated bedforms in the near-shore sand environment
Series Title: UFLCOEL
Physical Description: xii, 132 leaves : ill. ; 29 cm.
Language: English
Creator: Jettâe, Christopher D., 1969- ( Dissertant )
Hanes, Daniel M. ( Thesis advisor )
Dean, Robert G. ( Reviewer )
Mossa, Joann ( Reviewer )
Sheppard, Donald M. ( Reviewer )
Thicke, Robert J. ( Reviewer )
University of Florida -- Coastal and Oceanographic Engineering Dept
Publisher: Coastal & Oceanographic Engineering Dept., University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1997
Copyright Date: 1997
Subjects / Keywords: Sand waves   ( lcsh )
Ocean bottom   ( lcsh )
Marine sediments   ( lcsh )
Coastal and Oceanographic Engineering thesis, Ph. D   ( local )
Dissertations, Academic -- Coastal and Oceanographic Engineering -- UF   ( local )
Genre: bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )
Abstract: To measure bedform geometry, a high-resolution sea-bed profiling system has been developed. The multiple transducer array (MTA) consists of an array of ultra-sonic (5MHz) transducers. The first prototype MTA described herein measures two-dimensional bedform profiles over a length of 45 cm. Under ideal conditions, the instrument is capable of 1 mm vertical resolution and 2 cm horizontal resolution. Laboratory and field tests of the MTA show the system’s capability to accurately measure bedforms of known geometry and the ability to work under conditions with relatively high suspended sediment concentrations. Previous high-resolution profiling systems have either had moving parts, or have been unable to obtain the resolution of the system described herein. A multiple transducer array (MTA) was used to measure seabed geometry in a near-shore wave dominated environment in Duck, NC. The instruments were developed using a sensor insertion system (SIS) installed on the research pier. Bedforms were measured under a variety of wave conditions and at several cross-shore locations. Two existing empirical ripple prediction models are compared to the measured field data. A new model is also empirically determined from these measurements. This new model describes vortex ripple geometry strictly in terms of sediment and flow conditions and does not require the calculation of shear stress. When all available field measurements of small scale ripples are compared to these predictive models, the new model has lower errors in predicting ripple height, steepness, and length than any of the other models. Both small scale ripples with lengths of less than 40 cm, and large scale megaripples were measured during this experiment. Observations indicate that ripple flattening and reformation is a function of wave mobility number. Ripple reformation was commonly observed to occur in less than one minute after flattening and under certain conditions reformation was observed to occur within a few wave periods. Observations of megaripple migration indicate that cross-shore sediment transport due to ripple migration may be a significant process. Estimated cross-shore bed load transport rates are a good indicator of small scale ripple migration direction. Measurements indicate that megaripple lengths are proportional to near-bed orbital diameter, and that these types of bedforms can exist at small and large values of mobility number and orbital diameter.
Thesis: Thesis (Ph. D.)--University of Florida, 1997.
Bibliography: Includes bibliographical references (leaves 129-131).
Statement of Responsibility: by Christopher D. Jettâe.
Funding: This publication is being made available as part of the report series written by the faculty, staff, and students of the Coastal and Oceanographic Program of the Department of Civil and Coastal Engineering.
 Record Information
Bibliographic ID: UF00075478
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 41567372

Table of Contents
    Front Cover
        Front Cover
    Title Page
        Title Page
    Table of Contents
        Table of Contents 1
        Table of Contents 2
    List of Tables
        List of Tables
    List of Figures
        List of Figures 1
        List of Figures 2
        List of Figures 3
    List of symbols
        Unnumbered ( 10 )
        Unnumbered ( 11 )
        Abstract 1
        Abstract 2
        Page 1
        Page 2
        Page 3
    Previous work
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Multiple transducer array
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
    Field measurements of bedforms and a comparison of prediction techniques
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
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        Page 40
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        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
    Observations of bedform dynamics
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
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        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
    Discussion and conclusions
        Page 89
        Page 90
        Page 91
        Page 92
    Appendix A: SIS95 and SIS96 data and plots
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
    Appendix B: SIS95 and SIS96 programs and data file descriptions
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
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        Page 119
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        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
        Page 128
        Page 129
        Page 130
        Page 131
    Biographical sketch
        Page 132
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