OCE421 Marine Structure Designs

1. OCE421 Marine Structure Designs Lecture 1 Fall, 2006

2. OCE421: Marine Structure Designs, Fall 2006 Prerequisite: OCE307 Instructor: Dr. James Hu, Prof. in OE Office: Sheets Building, Rm. 220 Phone: 874-6688 Email: hu@oce.uri.edu Class Hours: M,W 2:00 -3:15 pm Class Room: Room 117, Sheets Building Office Hours: By appointment

3. Teaching Assistant Mr. Nate Greene Office Hours: TBA Office: 202 Sheets

4. Mailing List www/oce/uri/edu/ mailman/listinfo/oce421

5. Primary Textbook U.S. Army Corps of Engineers, (1984) Shore Protection Manual, Vol.1 and 2, Vicksburg, MS: Coastal Engineering Research Center. (it is now out-of-print) Coastal Engineering Manual (CEM) http://ocean.oce.uri.edu/cem/

6. Grading Policy Homework Assignments: 10% Mid-term Exam: 30% (10/23/2006) Quizzes: 30% Project Report and Presentation : 30%

7. Homework Assignments 5-6 homework assignments No late homework accepted Using MATLAB extensively

8. Project guideline, Fall 2006 2-person or 3-person teams allowed Project proposal: due Nov. 1 Final report: due Dec. 4 Presentation: Dec. 6 and Dec. 11

9. Project proposal must include: general statement (statement of problem) design site description proposed coastal structure map and bathymetry plot near the design site wave data base to be used

10. Final Project Report must include: general statement (statement of problem) design site description proposed coastal structure planning analysis map and bathymetry plot near the design site design wave and design water depth complete structural design cost analysis alternative design and cost analysis environmental impact analysis (optional) concluding remarks

11. Effects of Water Waves Waves are the major factor in determining the geometry and composition of beaches significantly influence the planning and design of harbors, waterways, shore protection measures, coastal structures, and other coastal works.

12. Physical Description of a water wave its surface form the fluid motion beneath the wave

13. Progressive/Standing Wave A waveform which moves relative to a fixed point is called a progressive wave; the direction in which it moves is termed the direction of wave propagation. If a waveform merely move up and down at a fixed position, it is called a standing wave or a clapotis.

14. Oscillatory/Nearly Oscillatory Waves Water waves are considered oscillatory or nearly oscillatory if the water particle motion is described by orbits that are closed or nearly closed for each wave period. The linear theory describes pure oscillatory waves. Most finite-amplitude wave theories describe nearly oscillatory waves since the fluid is moved a small amount in the direction of wave advance by each successive wave. This motion is termed mass transport of the waves.

15. Wave Classification by Wave Period One way to classify waves is by wave period, or the wave frequency. Of primary concern are gravity waves which have periods from 1 to 30 seconds. A narrower range of wave periods, from 5 to 15 seconds, is usually more important in coastal engineering problems.

16. Gravity Waves Surface tension forces may be neglected. Gravity is the dominant restoring force. Oscillatory water motion is the result of the interaction between gravity and inertia forces.

17. Seas and Swell Gravity waves can be separated into two states: Seas - when the waves are under the influence of wind in a generating area, and Swell - when the waves move out of the generating area and are no longer subjected to significant wind action.

18. Wave Parameters and Characteristics A (simple) wave is completely specified by wave height, the water depth, and the wave period (or wave length). Other characteristics of interest: Wave surface profile Forward speed (celerity) Particle velocities, accelerations, and motion paths Dynamic pressure field Kinetic and potential energy Wave power and momentum flux

19. Monochromatic and Irregular Waves Monochromatic waves – a single (deterministic) wave height and period. Irregular waves – statistical (probabilistic) distribution of wave heights and periods; and wave spectrum (wave “power” versus wave frequency)

20. Design Wave Conditions (for a specific location) Various design requirements – different types of design wave information are needed Effective wave measurement, analysis, and prediction techniques are needed.