| Author | Tran Phuong Dung |
| Call Number | AIT Thesis no.WA-94-15 |
| Subject(s) | Waves--Mathematical models
|
| Note | A thesis submitted in partial fulfillment of the requirements
for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | In the present study, a numerical model of nearshore currents
induced by wave was studied and verified with the result of an
experiment for the barred beach. A numerical model is divided into
two parts. First part is to compute the wave field by using the
elaborated model such as the time-dependent mild slope equation .
Second part is the 2 dimensions depth-average currents model for
nearshore currents induced by regular breaking wave. The general
two-dimensional basic equations combining effects due to refraction,
diffraction, shoaling and wave breaking are introduced in form of
the first order equations. The linear wave theory is applied in the
present study.
A series of measurement was carried out in the Hydraulic
Laboratory, with experimental setup built on basic of longshore
current measurement in the rectangular closed wave basin with a
longshore bar . Wave height and velocities of 2 directions in a 2 -D
coordinate system were recorded at more than 152 points by using a
wave gauge and an electromagnetic current meter through a converting
computer program.
The model was modified to simulate wave deformation and current
field with the same wave condition for an experimental area with
the same longshore bar . By the equation of eddy viscosity which was
proposed for plane beach, computational eddy viscosity h ad
discontinuity distribution around the bar crest for barred beach.
One improved equation for eddy viscosity was proposed without its
discontinuity and was used in computation of nearshore current .
Four runs with four different cases of dissipation factor were
computed . Computational results were not much significant different
between these four runs . Sensitivity analysis of friction coefficient
and constant for mixing formulae was carried out roughly. Through
comparison between experimental and computed results of both wave
h eight and velocities at many sections of many pair of values of
friction coefficient and constant for mixing formulae , the most
appropriate values of those parameters were found very low due to
high velocity result in experiment .
The obtained results draw the conclusion that the model can be
applied to accurately simulate the transformation of monochromatic
linear waves as they propagate over a barred beach configurations . |
| Year | 1994 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Resources Research Engineering (WA) |
| Chairperson(s) | Sutat Weesakul |
| Examination Committee(s) | Suphat Vongvisessomjai ;Imamura, Fumihiko ;Tran Thuc
|
| Scholarship Donor(s) | Denmark. |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1994 |