Topical Presentation to Visiting Student from Cheju National University, Korea

1. Notional Taiwan Ocean University Coastal Engineering－ Introductions Topical Presentation to Visiting Student from Cheju National University, Korea by Tzang, Shiaw－Yih Ph.D. Associate Professor Dept. of Harbor & River Eng. 9:00AM~12:00PM; Aug, 25th, 2005

2. Outlines • Definition in coastal Area • Coastal Hydraulics • Small – amplitude (SA) wave theory • Wave deformation • Wave Classification in the Ocean • Coastal Structures • Design Formula • Countermeasures for Coastal Protection • Failure events around NTOU seawalls by Typhoon Herb(1996)

3. Reference • Dean, R. G. and R. A. Dalrymple (1991) "Water Wave Mechanics for Engineers and Scientists", World Scientific (Advanced Series on Ocean Engineering, Vol. 2). • Silvester, R. (1974)Coastal Engineering, Ⅰ, Ⅱ, Elsevier Scientific Publishing Co. • Horikawa, K. (1978) "Coastal Engineering - An Introduction to Ocean Engineering“ University of Tokyo Presses. • Ou, S. H., Hsu, T. W. and Chang, H, K. (2001). Sustainable Diamond Coast – Prevention of Coastal Damages and Integrated Planning on sustainable Utilization of Coastal Ocean Space (in Chinese), Water Resources Bureau, MOEA, ISBN 957-02-8964-3. • Svendsen, IB. A.and I. G. Jonsson (1976) "Hydrodynamics of Coastal Regions", Lyngby, Den Private Ingeniørfond, Technical University of Demnark.

4. Definition inCoastal Area Geographical Configuration： Source: U.S Army Coastal Engineering Manual

5. Definition inCoastal Area Coastal Processes： Source：Svendsen & Jonsson(1976) "Hydrodynamics of Coastal Regions", Lyngby, Den Private Ingeniørfond, Technical University of Demnark.

6. or L ( T ) ( ) h H a x , t x t or ( ) h Coastal Hydraulics –SA Wave Theory (1) Wave definition： H：Wave height η：Water Surface elevation L：Wave length a：amplitude Source: Dean R.G. and R. A. Dalrymple (1984) “Water Wave Mechanics for Engineers and Scientists”

7. L (or T) z KFSBC DFSBC (x, y) H x (or t) LBC LBC h BBC Boundary value program specification for periodic water waves Coastal Hydraulics –SA Wave Theory (2) Assumptions： Potential Flow, In viscid Fluid ⇒ (Laplace Equ. for Velocity Potential ) Source: Dean R.G. and R. A. Dalrymple (1984) “Water Wave Mechanics for Engineers and Scientists”

8. Coastal Hydraulics –SA Wave Theory (3) Expressions： (Progressive wave ) （wave number） （angular frequency）

9. Water particle velocities in a progressive wave Coastal Hydraulics –SA Wave Theory (4) Exponentially decay with depth： Direction of progressive wave propagation z x=L x=L/2 x u w w u Source: Dean R.G. and R. A. Dalrymple (1984) “Water Wave Mechanics for Engineers and Scientists”

10. A z Water particle of interest B ξ ζ x ( x1 , z1 ) Coastal Hydraulics –SA Wave Theory (5) Elliptical form of water particle trajectory： Source: Dean R.G. and R. A. Dalrymple (1984) “Water Wave Mechanics for Engineers and Scientists”

11. In deep water ： shallow water： Coastal Hydraulics –SA Wave Theory (6) Dispersion equation： • σ& k or T & L are correlated, rather then independent • In deep water, longer waves propagate faster

12. Coastal Hydraulics –SA Wave Theory (7) Particle Trajectory： Source: Dean R.G. and R. A. Dalrymple (1984) “Water Wave Mechanics for Engineers and Scientists”

13. Wave Classification in the Ocean (1) A. By Period

14. Depth water： , shallow water： , intermediate： Wave Classification in the Ocean (2) B. By Water Depth Wind wave ： swell：

15. Caisson Caisson Coastal Structures – Design Formula (1) Structure Type： Totally reflected incident waves Vertical Composite Rubble – mound foundation Partially dissipating Waves Rubble Mound Rubble - Mound

16. P 1 h * Water Surface h 0 d h P u ¢ h P 2 P 3 Coastal Structures – Design Formula (2) Goda’s Formula： Deried from • 4th-order standing wave theory • Lab experiments • Case study on failure events Source：Goda, Y.“Random Seas and design of maritime structure,” university of Tokyo Press(1985)

17. Coastal Structures –Countermeasures for Coastal Protection Seawall：protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away. Breakwater：A structure that extends parallel to the shore at a defined offshore distance. Breakwaters trap sand behind them and also stop waves from breaking on the beach. Groin：structures built perpendicular (at a right angle) to the shoreline. Groins can trap sand moving alongshore and also stop sand from leaving. Works like a headland! Source：http://lighthouse.tamucc.edu/Main/GroinAndBreakwaterDefinition

18. Failure events around NTOU seawalls by Typhoon Herb (1996)(1) Typhoon path classification： 7 Special Case Paths of Typhoon Herb (1996 ) (Old 7 Paths) Source：Central Weather Bureau of R.O.C.

19. Pa-Chi-Men breakwater of port of Keelung Lod Pool breakwater of port of Keelung NTOU Seawall National Taiwan Ocean University Failure events around NTOU seawalls by Typhoon Herb (1996)(2) Failure Documents： Geographical locations：

20. Failure events around NTOU seawalls by Typhoon Herb (1996)(3) NTOU Seawall：

21. Failure events around NTOU seawalls by Typhoon Herb (1996)(4) Pa-Chi-Men Breakwater of Port of Keelung：

22. Failure events around NTOU seawalls by Typhoon Herb (1996)(5) Log Pool Breakwater of Port of Keelung：

23. Thanks for your attention !!