StudentShare
Contact Us
Sign In / Sign Up for FREE
Search
Go to advanced search...
Free

Refaction/Defraction at Coastal Structures - Essay Example

Comments (0) Cite this document
Summary
Water waves are created as a result of application of an external force, say a gust wind, working against the gravity and surface tension. These waves exhibit various phenomena like reflection, refraction, diffraction and shoaling. Phenomena like refraction and shoaling occur in shallow waters (Komar, P)…
Download full paperFile format: .doc, available for editing
GRAB THE BEST PAPER97.3% of users find it useful
Refaction/Defraction at Coastal Structures
Read TextPreview

Extract of sample "Refaction/Defraction at Coastal Structures"

--------------------------- --------------------------- --------------------------- --------------------------- Refaction/Defraction at Coastal Structures
Introduction
Water waves are created as a result of application of an external force, say a gust wind, working against the gravity and surface tension. These waves exhibit various phenomena like reflection, refraction, diffraction and shoaling. Phenomena like refraction and shoaling occur in shallow waters (Komar, P). Diffraction takes place when the waves encounter an obstacle or protrusion; say an island, in its path. In the subsequent paragraphs, we will elaborate on refraction and diffraction of water waves.
Wave Parameters and Wave Propagation
As much like electromagnetic or optical waves, water waves can be described by the basic parameters - height, length and period. In addition to the above parameters depth of water over which the wave travels also assumes importance (Dean, R.G. and Dalrymple, R.A). Distance between two consecutive crests is called the wave length while the time that elapses for two crests to pass a point is the period of the wave. These waves are associated with energy which is proportional to square of its height. A traveling wave carries this energy efficiently and the speed of energy travel is related to the wave speed, given by the product of wave length and reciprocal of wave period. As the wave approaches the shore or coastal line, it encounters change in water depth, that is, the wave enters shallow waters. The water is said to be shallow when one half of the wave length exceeds the depth of water.
Refraction
Refraction is the process by which the wave, while propagating in shallow water at an angle to the physical topographical contours, changes its direction so as to align to the contours (Wallingford, H.R.). As the wave propagates towards the shore, the depth of the water continuously decreases. As a result, the wave experiences varied depth. The speed of the wave is faster in deeper water. Thus, the parts of the wave travel at varying speeds. Part of the wave in the shallowest water is the slowest while the part in deepest water is the fastest. Thus, the wave bends with the variation of depth beneath the crest. Imagine a wave approaching a coast line at an angle. The wave crests nearer to the coast will slow down in comparison to the ones which are away. Thus the lagging wave crests will travel faster and catch up with the ones which are ahead. Thus, the wave crests will tend to become parallel to the coastline. Similarly, while approaching an island from one side, the crest will tend to wrap around the island reaching the beach close to parallel (Bascom, W.).
Diffraction
Wave diffraction is the process in which wave energy is transferred in lateral direction, perpendicular to the actual direction of propagation, from points of greater to lesser wave height along the crest (Mei, Chiag C). This happens whenever the waves encounter discontinuities in its field of travel. These discontinuities may be a surface-piercing obstacle, such as a breakwater or an island. To illustrate, consider a breakwater in the path of a water wave, propagating in the perpendicular direction to the breakwater. It may appear that the shadow region will remain disturbance free. However the wave disturbance gets transferred to shadow region also, by means of diffracting through finite length sheltered region (Dean, R.G. and Dalrymple, R.A).
Conclusion
Refraction and diffraction are the two phenomena involving change in wave direction. The latter effect is due to variations in depth of the water while the former is caused by the wave's interaction with the discontinuities like, breakwater or island.
References
Bascom, W. "Waves and beaches: the dynamics of the ocean surface." Garden City, NY: Doubleday & Co., Inc., 1964.
Dean, R.G. and Dalrymple, R.A., "Water wave mechanics for engineers and scientists." Singapore: World Scientific, 1991.
Mei, Chiag C. "The applied dynamics of ocean surface waves." United States of America: John Wiley & Sons, Inc, 1983.
Komar, P. "Beach processes and sedimentation." Englewood Cliffs, NJ: Prentice-Hall, Inc., 1976.
Wallingford, H.R. "A guide to managing coastal erosion in beach/dune system." Oct. 2000. Scottish Natural Heritage. 13 Feb. 2007 . Read More
Cite this document
  • APA
  • MLA
  • CHICAGO
(“Refaction/Defraction at Coastal Structures Essay”, n.d.)
Retrieved from https://studentshare.org/miscellaneous/1529518-refactiondefraction-at-coastal-structures
(Refaction/Defraction at Coastal Structures Essay)
https://studentshare.org/miscellaneous/1529518-refactiondefraction-at-coastal-structures.
“Refaction/Defraction at Coastal Structures Essay”, n.d. https://studentshare.org/miscellaneous/1529518-refactiondefraction-at-coastal-structures.
  • Cited: 0 times
Comments (0)
Click to create a comment or rate a document

CHECK THESE SAMPLES OF Refaction/Defraction at Coastal Structures

Radar Coastal Surveillance

.... 19 Figure 8. Synthetic aperture. 20 Figure 9. Equivalence of SAR and ISAR. 22 Figure 10. Coastal Surveillance Functions. 30 Figure 11. Surveillance Structure. 33 Figure 12. Port Monitoring System. 34 1.0 Research Approach 1.1 Aim The primary aim of the present research is the determination of the extent to which radar systems efficiently and effectively execute the requirements and tasks associated with coastal surveillance. Hew (2006), a defence systems analyst with the Defence Science and Technology Organisation, contends that no single radar system is capable of fulfilling the stated tasks and responsibilities but that coastal area characteristics have to be matched against specific systems. In other words, the selection...
20 Pages(5000 words)Essay

Coastal Defence

... s Coastal Defence The term 'coastal defence' is a much used, but much abused term for referring to any feature along the coast or estuary designed to protect a beach or land. It is more correct, however, to distinguish between two forms of coastal defence. First, flood or sea defences are structures used to prevent the land from being flooded by the sea; examples include earth embankments in estuaries. Second, there are coastal protection structures, a term used to describe measures taken to prevent the land from being eroded, such as sea walls along the base of cliffs. (Cooper 9-15) In estuaries, tidal processes facilitate the accumulation of thick deposits of sand, silt, and clay, reaching to the upper limit of the tidal range...
4 Pages(1000 words)Essay

Wave Overtopping on Coastal Structures

...Wave-Topping On Coastal Structures: Introduction: Breakwaters are used extensively along coastlines all over the Earth and those that can allow wave overtopping without significant damage to effective structures and, thus, to properties and life they shelter are considered of eminent construction. Wave overtopping is a violent natural phenomenon that causes serious damage to protecting structures and life and property along coastlines (Shao, 2006). Traditionally, laboratory experiments and field observations have been used to study this turbulent oceanographic phenomenon and empirical formulae have been derived from these but severe limitations existed since parameters to which these derivations fitted were local (Shao, 2006). Thus...
14 Pages(3500 words)Essay

Wave Overtopping and Coastal Structures

...Part Two: Wave Overtopping on Coastal Structures Introduction: In the earlier parts of the paper a set of formulae developed by separate groups of researchers have been used to compare results of wave overtopping discharge volumes and individual wave overtopping volumes to investigate how each of these formulae approach the overtopping problem that poses a threat to coastal structures. Wave structural parameters used had been acquired from Shao, 2006, and it had been found that those former parts that the Shao, 2006, turbulence model was the most appropriate as it took into consideration a larger number of parametric values pertaining to wave and coastal protection structures. Nevertheless, the other formulae, listed hereafter, also...
9 Pages(2250 words)Essay

Refraction/diffraction at coastal structures

...Refraction and Diffraction at Coastal Structures This paper explores the processes of refraction and diffraction at coastal structures, and the significance these two processes hold for other coastal processes. There is a mathematical interpretation of some of the basic properties of these two phenomena. The historical background of this topic is discussed. Finally, the potential for further research is considered. Wave diffraction is the process in which the energy of water waves spread out through a narrow opening, such as a harbor mouth. When a water wave passes an island, the waves bend into the shadow region on the lee side of the island. This effect is due to the changes in wave height along the crest of the same wave (“Shoaling...
4 Pages(1000 words)Essay

Coastal Zone Management Policy

“The national CZM Program is based on the federal Coastal Zone Management Act of 1972, which is implemented by the National Oceanic and Atmospheric Administration (NOAA) through the Office of Ocean and Coastal Resource Management. The Coastal Services Center is a program within the National Oceanic and Atmospheric Administration devoted to serving the nation's state and local coastal resource management programs by linking people, information, and technology.” (Coastal Zone Management)

Coastal zone management is very essential because there have been a lot of changes in the global environment in recent decades. There must also be the development of these resources for better utilization and bringing awarenes...

12 Pages(3000 words)Case Study

Managing coastal environments

...Management Coastal Environment Final Synthesis Paper Q1. Coastal erosions can be considered as one of the significant processes in the natural environment. There are two classifications of erosions in the coastal environment namely the natural erosion and the human induced erosion. Natural erosion is mainly caused by different factors and components of the natural environment such as storms and the movement of sediments. Another type is the human induced erosion which is caused by human activities or developments. Due to the effects that can be brought about by erosion, humans had developed actions to be able to achieve a perceived protection from the said environmental phenomenon. In 1950-1970s, one of the methods used to achieve...
4 Pages(1000 words)Essay

Coastal engineering

...Coastal Engineering Introduction: The Ocean waves are formed by interactions of   the moon, sun, and earth. The moon and earth are like magnets thatattract. When the moon pulls on the Earth, the earth cant hold on to the water because it is always moving, so the moons gravity pulls on the ocean tugging at the water causing it to sway and move thus this tugging and saying causes the surface to take on the form of a wave. The communities and industries along the coastal zone heavily rely on this zone. Engineers are working very hard to make sure these communities and the industries survive the strong effect of the forces of the nature provided by the waves and the tides. This has brought about constant developments and maintenance...
10 Pages(2500 words)Assignment

Coastal Development

...Coastal Development al Affiliation Coastal Development Hurricane Sandy is arguably the worst hurricane ever witnessed in U.S. history. The Hurricane Sandy that hit the U.S. coastline on October 2012 caused massive destruction to properties on the coastline and left hundreds of people dead (Foster, 2014). Official report released after the disaster confirmed that at least 117 American citizens perished in the disaster while 69 others died in Canadian and Caribbean coastline making the hurricane the deadliest and most destructive hurricane disasters ever. However, evidences point that the destruction caused by the hurricane could have been minimized if proper measures were put by homeowners and contractures at the affected coastlines...
1 Pages(250 words)Assignment

Structures

...Introduction to Engineering Design ENF1204 0Executive summary Comprehending structural behavior of any bridge is a significant aspect of engineering. This is because it aids in comprehension of the concepts of load transfer via the structure by tension and compression and corresponding equilibrium of underlying forces within a static analysis of the structure. The report aims at analyzing the construction and testing of the prevailing under sluing truss bridge with close attempt of coming up with suitable conclusions concerning the behavior and the corresponding challenges normally encountered by the real world of engineers. The bridge was built to a scale of 1 to 40 with total clearance span of 500mm, utilizing craft sticks and PVA glue...
4 Pages(1000 words)Essay

Confucian influence to Korean society : Social structures and Women's status in Yi Dynasty (Choson:1392-1910)

...[Name of writer appears here] [Course name appears here] [Professor’s name appears here] [Date appears here] Confucian Influence to Korean Society: Social Structures and Women's Status in Yi Dynasty Introduction The beginning of Confucian notion as part of the cultural exchange from China is one of the most significant influences in Korean intellectual history. Thus the ideology that undergirded Korea's relations with Ming China was Neo-Confucianism, which arose in Sung China during the eleventh and twelfth centuries. It started as a result of attempts to cause the ideological unification of China in the face of "barbarian" assaults on Chinese civilization. In response to the metaphysical challenges posed by Buddhism and Taoism, Neo...
8 Pages(2000 words)Essay

Can Perceived Fairness in Reward Structures Be Unanimous

...Can Perceived Fairness in Reward Structures be Unanimous? In today’s intensely competitive business environment, competitive advantages are hard to achieve and sustain. More and more organisations are changing the manner in which organisation manages itself and aims at deriving a competitive advantage through its human capital. This involves increasing productivity, efficiency and reducing costs through numerous aspects of human resource management. Developing reward systems, which link corporate objectives to human resource strategies, is essential in the process of gaining such strategic advantages. In administering a reward system, it should fulfill numerous objectives including, acquiring of qualified personnel, retain present...
13 Pages(3250 words)Assignment

Different Organisational Structures of Japan, Germany and the UK

It is for this reason, that the competition in modern markets has become extremely high and the survival of companies within the international commercial marketplace has become a challenging target. On the other hand, the study of Gooderham et al. (1999, 507) proved that “despite their very different assumptions, both rational and institutional explanations of organizational structure and management practices predict similarity among firms that operate in the same industry within the context of a simple country”. In other words, the structural and operational patterns of firms worldwide are similar although significant differences in culture may exist. It should be noticed however that these similarities are limited. T...
13 Pages(3250 words)Assignment

The Various Elements of British Social Structures

A professor of sociology at Warsaw University, he suddenly found it necessary to locate a new home and position when communist authorities questioned the value of his lessons. From Warsaw, Bauman went on to lecture at the universities of Tel Aviv and Haifa until 1971 when he traveled to England and accepted a permanent post at the University of Leeds (Decjusza, 2000). He has also been a visiting professor at Berkeley, Yale, Canberra, St. John’s and Copenhagen. Throughout, and especially after his retirement from Leeds in 1990, he has written numerous books and essays, identifying and introducing the concept of postmodernism, turning in recent years to new terminology that describes a liquid culture. To understand the impact...
9 Pages(2250 words)Case Study

A Comparative Analysis of Four Major Market Structures

...Market structures determine the behavior of the participants of a market. There are different market structures that affect the way a business operates in terms of strategic options such as pricing strategy, long term position, reaction to other participants, and entry position among other variables. The four major market structures are perfect competition, monopolistic competition, oligopoly and monopoly. This paper focuses on perfect competition by examining the pro and cons, strategic alternative, pricing policy of firms participating in this market and it provides a comparative analysis of all four major market structures. A barrier of entry is a constraint that limits the entrance of new competitors into an established marketplace...
7 Pages(1750 words)Term Paper

Modern Approach Towards Controlling the Response of Structures Towards Winds and Earthquakes

...Contents Page No. Introduction 3 Content 4 ification of the modern structural control mechanism 5 Conclusion 9 References 11 Modern approach towards controlling the response of structures towards winds and earthquakes: Introduction: Achieving control over the response of a structure to the stresses induced in it by the large natural forces of earthquakes and wind storms and designing various vibration control techniques are some of the most fundamental areas which are studied in the Structural Dynamics. One of the biggest concerns while designing a multi storey building, a bridge or a skyscraper is to estimate the deformations the structure is likely undergo as a result of taking natural and unpredictable loads brought by high speed...
8 Pages(2000 words)Coursework

Hydraulic Structures

...TABLE OF CONTENTS CONTENTS PAGE Introduction 2. Hydraulic Structures 2 Hydraulic Engineering Structures 2 2.1.1 General Hydraulic Engineering Structures 2 2.1.2 Special Hydraulic Engineering Structures 2 2.2 Design of Hydraulic Structures 3 2.3 Different Hydraulic Structures 3 2.3.1 Storage Dams 4 2.3.2 Spillway 5 2.3.3 Outlet Works 5 2.3.4 Diversion Works 6 2.3.5 Drop Structures 6 2.3.6 Stone Structures 7 2.3.7 Conveyance and Control Structures 7 2.3.8 Culverts and Measurement of Flow 7 3. Conclusion 8 References i Appendix A (A Spillway) ii Appendix B (Canal Drop Structure from Lee Lake) iii Appendix C (Bottom Outlet...
8 Pages(2000 words)Research Paper

International Relations: Structures of International Governance

... International Relations - Structures of International Governance Critically assess the relationship between intergovernmental organizations and non-governmental organizations. Illustrate your argument with an empirical example Introduction Non-state actors have come to exert an increased influence on the decision-making and management activities of the leading international financial institutions and other major sectors of different countries. There are three main broad categories of non-state actors, non-governmental organizations, standard setting institutions, and credit rating agencies; each of them play a vital and distinct role in the development of any country (Haque, 2000). Global governance seek the change in the politics...
8 Pages(2000 words)Term Paper

Coastal Storm Defenses

... onto an eroding shoreline. It replaces beach or cliff material that has been removed by erosion or long shore drift. Usually sand is filled once in a year, and is relatively inexpensive option, but it requires constant maintenance. Breakwaters are structures constructed on coasts as part of coastal defense to protect a harbor from wave energy or deflect currents. They are constructed either some distance away from the coast or built with one end linked to the coast. Cheaper materials like rubber tires and oil drums are usually used for its construction. They may be either fixed or floating depending on normal water depth and tidal range. When waves hit these breakwaters, their erosive power is concentrated on these structures some...
9 Pages(2250 words)Assignment

The Effect of the Uncanny Through Narrative Structures

...The Effect of ‘The Uncanny’ Through Narrative Structures The uncanny is often a reverse of what is known to us, and according to Freud, it is a situation where something can be familiar and foreign simultaneously (Bartnæs 2010, p.33), thereby yielding the feeling of it being disturbingly strange or unnervingly familiar. In this respect, the uncanny may seem familiar, but its familiarity will always be unsettling, troubling, and frightening at the same time; Freud proposes that such familiarity could be attributed to the repressed emotions in the unconscious mind, and the worry over the reoccurrence of such trauma. Elements of the uncanny include doubles/repetition, robots/automatons, a focus on the eyes, and a feeling eeriness that results...
10 Pages(2500 words)Case Study
sponsored ads
We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.

Let us find you another Essay on topic Refaction/Defraction at Coastal Structures for FREE!

Contact Us