4.2. SHORT-WAVE HYDRODYNAMIC MODELS
85
• Development of qualitative information (via tracers) on the
effects of structures on the littoral processes.
• Stabilization of entrance structures.
• Development of remedial plans for alleviation of undesirable conditions as found necessary.
• Evaluation of proposed design modifications which could
significantly reduce construction costs and still provide adequate harbor protection.
Naturally, in order to accomplish any of the above tasks, the harbor
model must be constructed accurately to reproduce prototype conditions,
and the model boundary conditions must be well established. If these
conditions are met and economic considerations justify the use of a physical
modeling approach, then a physical harbor model is still the best way to
examine short-wave effects within and adjacent to the harbor.
Gravity waves are defined as short waves when (e.g., Yalin 1971)
%
h
1
kh > — or
— > —
10
L 20
(4.1)
where k is wavenumber, h is water depth, L is wavelength, and k and L are
related by the expression k — 2%/L.
Physical models of short waves are considered to be nondissipative or
fully turbulent (Le Méhauté 1976). In other words, the scaling of shortwave models assumes that waves experience negligible energy loss due to
friction prior to wave breaking; and when energy is lost, it is lost entirely
through turbulent dissipation processes, such as associated with the breaking mechanism. Le Méhauté (1976) stateed that most coastal models can
be considered short-wave models, and as we shall see in the next section,
it is important that the models be geometrically undistorted in the length
scale.
The following is a partial list illustrating the types of coastal problems that can be studied in a short-wave, fixed-bed hydrodynamic physical
model. In any of the listed studies, waves could be either monochromatic
or irregular in character.
• Wave shoaling (2-d and 3-d)
• Wave kinematics (2-d and 3-d)
• Wave refraction (3-d)
• Wave diffraction (3-d)
• Nonlinear wave mechanics (2-d and 3-d)
85
• Development of qualitative information (via tracers) on the
effects of structures on the littoral processes.
• Stabilization of entrance structures.
• Development of remedial plans for alleviation of undesirable conditions as found necessary.
• Evaluation of proposed design modifications which could
significantly reduce construction costs and still provide adequate harbor protection.
Naturally, in order to accomplish any of the above tasks, the harbor
model must be constructed accurately to reproduce prototype conditions,
and the model boundary conditions must be well established. If these
conditions are met and economic considerations justify the use of a physical
modeling approach, then a physical harbor model is still the best way to
examine short-wave effects within and adjacent to the harbor.
Gravity waves are defined as short waves when (e.g., Yalin 1971)
%
h
1
kh > — or
— > —
10
L 20
(4.1)
where k is wavenumber, h is water depth, L is wavelength, and k and L are
related by the expression k — 2%/L.
Physical models of short waves are considered to be nondissipative or
fully turbulent (Le Méhauté 1976). In other words, the scaling of shortwave models assumes that waves experience negligible energy loss due to
friction prior to wave breaking; and when energy is lost, it is lost entirely
through turbulent dissipation processes, such as associated with the breaking mechanism. Le Méhauté (1976) stateed that most coastal models can
be considered short-wave models, and as we shall see in the next section,
it is important that the models be geometrically undistorted in the length
scale.
The following is a partial list illustrating the types of coastal problems that can be studied in a short-wave, fixed-bed hydrodynamic physical
model. In any of the listed studies, waves could be either monochromatic
or irregular in character.
• Wave shoaling (2-d and 3-d)
• Wave kinematics (2-d and 3-d)
• Wave refraction (3-d)
• Wave diffraction (3-d)
• Nonlinear wave mechanics (2-d and 3-d)