Numerical Simulation of Irregular Wave Run-Up on a Beach

Master's Thesis
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Abstract

Hurricane is a common natural disaster. In natural hurricanes, irregular waves will shoal with decreasing depth when moving toward the beach. Once the wave height depth ratio exceeds a critical value, waves will break and generate a bore in the surf zone. Breaking waves will continue to propagate onshore and scour coastal zones. Breaking wave induced run-up can significantly risk infrastructure in coastal areas. For instance, run-up height can cause coastal flooding. Moreover, the momentum flux transported onshore can also exert forces on beaches and coastal structures. Therefore, properly simulating this process is a supplement of in-situ field measurement and is of great importance for coastal structure design. Previous studies have already shown the potential in numerically simulating the wave run-up in lab length scales and in short time scales (less than half hour).In my study, long time (1h) wave run-up will be simulated on larger scale domains .

Numerical run-up results are compared with Stockdon’s formula [1] and two percent exceedance run-up elevation is used for comparison. The result shows that two dimensional run-up height is always higher than Stockdon’s formula because two dimensional simulation doesn’t consider directional spreading angle . In three dimensional cases, directional spreading plays an important role in mitigating run-up height. Result shows that run-up heights calculated by Stockdon’s formula are very close to numerical results when directional spreading angle . Furthermore, my study calculates 0.5% exceedance dimensionless momentum flux, noting its variation with different surf simulation numbers , dimensionless elevation and directional spreading angle. Result shows that the extreme momentum flux decreases with increasing elevation. Furthermore, given a location, waves with bigger Iribarren number will generate a higher momentum flux. However, momentum flux cannot be expressed as a simple function of aforementioned parameters. By further investigation, a simple model is established to approximate 0.5% momentum flux.

Attributes

Attribute NameValues
Author Luning Sun
Contributor Andrew Kennedy, Research Director
Degree Level Master's Thesis
Degree Discipline Civil and Environmental Engineering and Earth Sciences
Degree Name MSCE
Defense Date
  • 2018-04-25

Submission Date 2018-07-08
Subject
  • Irregular wave run-up

Language
  • English

Record Visibility and Access Public
Content License
  • All rights reserved

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