Module 5 Orson P. Smith, PE, Ph.D. Professor Emeritus Refraction and shoaling analysis Using graphs Case studies Homer Spit RCPWAVE analysis Nikiski STWAVE analysis Orson Smith, PE, Ph.D., Instructor 1
Consider straight wave crests approaching shallow water at an angle Part of crest slows before rest Crest bends in toward shore Snell s Law: sin C sin cos cos 0 0 C0 C C0 Refraction Coefficient: K r cos 0 H H KsKr H cos 0 0 C 2C 0 0 g cos cos Orson Smith, PE, Ph.D., Instructor 2
Variation of C and at contour of arbitrary orientation (fig. 5.2 & eqn. 5.2 5.7 in text) 1 1 In terms of 2 : Solve this for each single depth cell in grid Curvature of wave ray depends on gradient of C normal to wave direction: ray bends toward lower C Lateral transfer of wave energy into a geometric shadow Orson Smith, PE, Ph.D., Instructor 3
Figures in CEM Part II, Ch. 7, after: Goda, Y., 2010. Random Seas and Design of Maritime Structures, 3 rd ed., Advanced Series on Ocean Engineering: Volume 33, World Scientific S max = 10 (wind waves, i.e., seas); S max = 75 (swell) y/l x/l Orson Smith, PE, Ph.D., Instructor 4
Figures in CEM Part II, Ch. 7, after Goda (2010) B/L = gap wavelength ratio period height B Figures in CEM Part II, Ch. 7, after Goda (2010) B/L = gap wavelength ratio period height ratio Orson Smith, PE, Ph.D., Instructor 5
Figures in CEM Part II, Ch. 7, after Goda (2010) B/L = gap wavelength ratio Figures in CEM Part II, Ch. 7, after Goda (2010) B/L = gap wavelength ratio Orson Smith, PE, Ph.D., Instructor 6
prevailing longshore sediment transport Coos Bay, Oregon Rogue River entrance, Oregon Case Study A: 1985 Ref. Smith et al, 1985 (Waterways Experiment Station report) Orson Smith, PE, Ph.D., Instructor 7
Module 5 Working with refraction and Orson Smith, PE, Ph.D., Instructor 8
Orson Smith, PE, Ph.D., Instructor 9
RCPWAVE numerical wave refraction, shoaling, and breaking model Steady state, linear waves monochromatic No open coast use only Ref. Smith et al, 1985 (Waterways Experiment Station report) Orson Smith, PE, Ph.D., Instructor 10
Case Study B: 2002 2003 Orson Smith, PE, Ph.D. Professor, UAA School of Engineering Alexander Khokhlov, MS Candidate, Dept. of Civil Engineering, UAA School of Engineering William J. Lee, Research Associate and Ph.D. candidate, Environmental Engineering Program, UAA School of Engineering Steven Buchanan, RLS, Instructor, Dept. of Geomatics, UAA School of Engineering Orson Smith, PE, Ph.D., Instructor 11
Project Sponsors Geomega, Inc. (Boulder, CO) Chevron Environmental Management Company (San Ramon, CA) Phase I Scope Investigate geomorphologic change through history of the site and survey data measured by UAA Sample and classify beach materials Characterize wave climate Numerical simulations of nearshore wave transformation Interpret geomorphologic changes with regard to local conditions Orson Smith, PE, Ph.D., Instructor 12
East Foreland Rigtenders Dock Mean Mean Spring Tide North West Range Range Level Station Latitude Longitude (ft) (ft) (ft) Ushagat Island, Barren Islands 58 57' 152 16' 11.4 13.7 7.2 SELDOVIA, Kachemak Bay 59 27' 151 43' 15.5 18.0 9.4 Homer, Kachemak Bay 59 38' 151 27' 15.7 18.1 9.5 Anchor Point 59 46' 151 53' 15.9 18.3 9.6 Cape Ninilchik 60 01' 151 43' 16.5 19.1 10.1 Ninilchik 60 03' 151 40' 16.7 19.1 10.0 Kenai River entrance 60 33' 151 17' 17.7 20.7 11.0 Kenai City Pier 60 33' 151 14' 17.5 19.8 10.4 Nikiski 60 41' 151 24' 17.7 20.5 10.9 East Foreland 60 43' 151 25' 18.0 21.0 11.2 Sunrise, Turnagain Arm 60 54' 149 26' 30.3 33.3 17.1 ANCHORAGE, Knik Arm 61 14' 149 53' 25.9 28.8 15.2 North Foreland 61 03' 151 10' 18.3 21.0 11.3 Drift River Terminal 60 34' 152 08' 15.4 18.1 9.7 Oil Bay, Kamishak Bay 59 38' 153 16' 12.6 13.9 7.3 Orson Smith, PE, Ph.D., Instructor 13
Composite hourly data Kenai Airport (1973 1997) KPC Terminal, Nikiski (1997 2002) Radial scale is percent frequency of occurrence Radial bands indicate 10 knot wind speed classes acting toward the center Wind rose analysis software and graphic by Josh Rogers, UAA School of Engineering Wind Speed Speed m/sec 0-9 (5) knots 2.57 10-19 (15) knots 7.72 20-29 (25) knots 12.86 30-39 (35) knots 18.01 40-49 (45) knots 23.15 50-59 (55) knots 28.29 Wave parameter 180 deg 202.5 deg 225 deg 247.5 deg 270 deg 292.5 deg 315 deg H 0.16 0.17 0.17 0.16 0.14 0.13 0.14 T 1.56 1.77 1.70 1.55 1.43 1.34 1.39 H 0.83 1.53 1.23 0.87 0.68 0.56 0.63 T 3.28 4.56 4.01 3.37 2.98 2.72 2.87 H 1.43 3.19 2.32 1.64 1.28 1.06 1.18 T 4.35 6.43 5.48 4.55 4.01 3.64 3.86 H 1.98 4.87 3.40 1.62 T 5.21 7.90 6.64 4.41 H 2.49 6.56 4.45 2.66 T 5.94 9.16 7.64 5.60 H 2.96 8.25 5.45 T 6.58 10.27 8.52 calculated using CEDAS ACES wave prediction software ( Veri Tech, Inc.) Orson Smith, PE, Ph.D., Instructor 14
Extreme Waves Offshore of the Mouth of the Kenai River, 1973-2000 Probability of H<H' 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Estimated Function Data, 1973-2000 0 5 10 15 20 25 30 Wave Height, H' (ft) Extremal wave analysis by Heike Merkel from previous study sponsored by PN&D, Inc., and City of Kenai Beach ice grows in upper tidelands and floats free to form sediment laden conglomerates Average ice conditions 1 15 February, showing color codes of concentration from 0 (no ice) to 10 tenths (100% ice cover) and hatch patterns to indicate stage of development (from Cook Inlet Ice Atlas by CRREL and UAA for NOAA, 2000) Orson Smith, PE, Ph.D., Instructor 15
Sample No. 3, 4, 6, & 7 100 80 #4: substrate below #3 Percent Finer 60 40 20 0 #3: surface just north of dock #6: surface, just south of open-cell wall #7: surface 40 ft off southern open-cell wall 100 10 1 0.1 0.01 Grain Size, mm Samples collected by Alexander Khokhlov Analysis by Curtis Townsend, UAA Civil Engineering student Orson Smith, PE, Ph.D., Instructor 16
# # # # # # # # # # # Module 5 Working with refraction and 586800 587000 587200 587400 587600 6729800 13 6729800 12 6729600 110 100 11 10 6729600 90 80 6729400 70 MLLW 60 50 40 30 20 10 6729400 7 9 8 6729200 5 6 3, 4 1, 2 6729000 6729200 6729000 6728800 6728600 N 100 0 100 Meters 300 0 300 Feet UTM Zone 5 (Meters) NAD 83 586800 587000 587200 587400 587600 6728800 6728600 Topographic survey: Steve Buchanan, RLS, Heike Merkel, Alissa Pempek, Josh Rogers, Alexander Khokhlov Hydrographic survey: Bill Lee, Alexander Khokhlov, Orson Smith Low tide view of North inshore corner of Rigtenders Dock, July 2002. Orson Smith, PE, Ph.D., Instructor 17
Grid developed by Alexander Khokhlov and Bill Lee from NOAA archives and UAA 2002 survey data for STWAVE simulations Steady state linear waves Evolution of directional spectrum Multiple waves of different H, T, and Non linear transfer of energy within spectrum Bottom friction, percolation, wind input, simple current interaction, breaking Diffraction past simple structures Orson Smith, PE, Ph.D., Instructor 18
STWAVE output for Hs = 5.45 m, Tp = 9.09 sec, direction = 225 T (from southwest). Arrows are wave rays, contours are wave height, and colors are depths at mean tide level. Climatic average condition: H = 0.6 m (2 ft), T = 4.2 sec, direction = 24 Northward Beach barrier (Rigtenders Dock) blocks longshore transport from South Orson Smith, PE, Ph.D., Instructor 19
Offshore margin of Rigtenders Dock at low tide. Orson Smith, PE, Ph.D., Instructor 20
Phase II Scope Extended numerical simulations 2 nd topographic & hydrographic survey Quantitative analysis of annual change Wave measurements Evaluation assumptions based on hindcast wave climatology Discuss alternative engineering responses to erosion Example BMAP analysis of profile change and of beach fill configurations Example BMAP analysis of profile change and of beach fill configurations Orson Smith, PE, Ph.D., Instructor 21
Orson Smith, PE, Ph.D., Instructor 22 Not For Navigational Use Not Fo N E W S58 46'58 52'58 58'59 2'59 6'59 10'59 16'59 22'59 28'59 34'59 40'59 46'59 52'59 58'60 2'60 6'60 10'60 16'60 22'60 28'60 34'60 40'60 46'60 52'60 58'61 2'61 6'61 10'61 16'61 22'154 48'154 48'154 36'154 36'154 24'154 24'154 12'154 12'154 00'154 00'153 48'153 48'153 36'153 36'153 24'153 24'153 12'153 12'153 00'153 00'152 48'152 48'152 36'152 36'152 24'152 24'152 12'152 12'152 00'152 00'151 48'151 48'151 36'151 36'151 24'151 24'151 12'151 12'151 00'151 00'150 48'150 48'1515Grid development by Alexander Khokhlov and Bill Lee, UAA/SOE NOAA Chart 16660 NOAA Chart 16640
Orson Smith, PE, Ph.D., Instructor 23
Orson Smith, PE, Ph.D., Instructor 24
Seawall Orson Smith, PE, Ph.D., Instructor 25
Data collected from 2003/06/09 13:36:40 to 2003/07/18 11:36:39 468 sea state measurements, 8.41 MB Sample rate = 2 Hz, burst length = 1,024 seconds (2048 samples) every 2 hours Spectral analysis: Frequency minimum = 0.04 Hz, Ensemble average every 128 samples Hanning type smoothing of ensembles Wave height (from ADP data) and Wind speed (from NOAA database) Nikiski (06/09/2003-07/18/2003) 15 2.5 14 13 12 2 Wind speed (m/s) 11 10 9 8 7 6 5 4 3 2 1 0 1.5 1 0.5 0 Wave height (m) Date 6/10/2003 6/11/2003 6/12/2003 6/13/2003 6/14/2003 6/14/2003 6/15/2003 6/16/2003 6/17/2003 6/18/2003 6/19/2003 6/20/2003 6/21/2003 6/22/2003 6/23/2003 6/24/2003 6/25/2003 6/25/2003 6/26/2003 6/27/2003 6/28/2003 6/29/2003 6/30/2003 7/1/2003 7/2/2003 7/3/2003 7/4/2003 7/5/2003 7/6/2003 7/6/2003 7/7/2003 7/8/2003 7/9/2003 7/10/2003 7/11/2003 7/12/2003 7/13/2003 7/14/2003 7/15/2003 7/16/2003 7/17/2003 7/17/2003 Date Wind Speed (m/s) Wave Height (m) Analysis and graph by Alexander Khokhlov, UAA/SOE Orson Smith, PE, Ph.D., Instructor 26
Orson Smith, PE, Ph.D., Instructor 27