OCE421 Marine Structure Designs

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OCE421 Marine Structure Designs

• Lecture 1
• Fall, 2006

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OCE421 Marine Structure Designs, Fall 2006

• Prerequisite OCE307
• Instructor Dr. James Hu, Prof. in OE
• Office Sheets Building, Rm. 220
• Phone [phone]
• Email hu_at_oce.uri.edu
• Class Hours M,W 200 -315 pm
• Class Room Room 117, Sheets Building
• Office Hours By appointment

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Teaching Assistant

• Mr. Nate Greene
• Office Hours TBA
• Office 202 Sheets

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Mailing List

• www/oce/uri/edu/
• mailman/listinfo/oce421

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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/

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Grading Policy

• Homework Assignments 10
• Mid-term Exam 30 (10/23/2006)
• Quizzes 30
• Project Report and Presentation 30

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Homework Assignments

• 5-6 homework assignments
• No late homework accepted
• Using MATLAB extensively

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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

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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

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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

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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.

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Physical Description of a water wave

• its surface form
• the fluid motion beneath the wave

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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.

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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.

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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.

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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.

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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.

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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

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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)

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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.