The fundamental and maximum period (Tn for n = 1) becomes
T =_-5_
(3-43)
1
VgJ'
Equation 3-43 is called Merian’s formula. (Sverdrup, Johnson and Fleming,
1942.)
In an open rectangular basin of length ^b' and constant depth d,
the simplest form of a one-dimensional, non-resonant, standing longitudinal wave is one with a node at the opening, antinode at the opposite end*
and nz nodes in between. (See Figure 3-40(C).) The free oscillation
period T^/ in this case is
^rtz
Tî i â
/' ’ ix •
(3-44)
(l+2n)Vgd
v
For the fundamental mode (nz = 0), T^
becomes
rp /
The basin*s total length
°
’
is occupied by one-fourth of a wave length.
(3-45)
This simplified theory must be modified for most actual basins,
because of the variation in width and depth along the basin axes.
Defant (1961) outlines a method to détermine the possible periods for
one-dimensional free oscillations in long narrow lakes of variable width
and depth. Defant’s method is useful in engineering work because it permits
computation of periods of oscillation, relative magnitudes of the vertical
displacements along chosen axes, and the positions of nodal and antinodal
lines. This method, applicable only to free oscillations, can be used to
détermine the nodes of oscillation of multinodal and uninodal seiches.
The theory for a particular forced oscillation was also derived by Defant
and is discussed by Sverdrup et al (1942). Hunt (1959) discusses some
complexifies involved in the hydraulic problems of Lake Erie, and offers
S01^tl°n *° the Pr°blem of vertical displacement of water at
eastern end of the lake. More recently, work has been done by Simpson
Rock^lirnSftL
’ P1“z”an and Ra° 0963), and Mortimer (1965).
the Great
fYSt five modes of oscillation for each of
Plltz^n \197n h a ProÇedu« based on the work of Platzman and Rao (1965).
basin^ôf .en.tî
dT P
a meth°d for evaluating natural periods for
basins of general two-dimensional configuration.
3.85 WAVE SETUP
levpiiniTr°cherVa^iOnS^ndiCate that Part
th® variation in mean water
level near shore is a function of the incoming wave field. However these
3-80
T =_-5_
(3-43)
1
VgJ'
Equation 3-43 is called Merian’s formula. (Sverdrup, Johnson and Fleming,
1942.)
In an open rectangular basin of length ^b' and constant depth d,
the simplest form of a one-dimensional, non-resonant, standing longitudinal wave is one with a node at the opening, antinode at the opposite end*
and nz nodes in between. (See Figure 3-40(C).) The free oscillation
period T^/ in this case is
^rtz
Tî i â
/' ’ ix •
(3-44)
(l+2n)Vgd
v
For the fundamental mode (nz = 0), T^
becomes
rp /
The basin*s total length
°
’
is occupied by one-fourth of a wave length.
(3-45)
This simplified theory must be modified for most actual basins,
because of the variation in width and depth along the basin axes.
Defant (1961) outlines a method to détermine the possible periods for
one-dimensional free oscillations in long narrow lakes of variable width
and depth. Defant’s method is useful in engineering work because it permits
computation of periods of oscillation, relative magnitudes of the vertical
displacements along chosen axes, and the positions of nodal and antinodal
lines. This method, applicable only to free oscillations, can be used to
détermine the nodes of oscillation of multinodal and uninodal seiches.
The theory for a particular forced oscillation was also derived by Defant
and is discussed by Sverdrup et al (1942). Hunt (1959) discusses some
complexifies involved in the hydraulic problems of Lake Erie, and offers
S01^tl°n *° the Pr°blem of vertical displacement of water at
eastern end of the lake. More recently, work has been done by Simpson
Rock^lirnSftL
’ P1“z”an and Ra° 0963), and Mortimer (1965).
the Great
fYSt five modes of oscillation for each of
Plltz^n \197n h a ProÇedu« based on the work of Platzman and Rao (1965).
basin^ôf .en.tî
dT P
a meth°d for evaluating natural periods for
basins of general two-dimensional configuration.
3.85 WAVE SETUP
levpiiniTr°cherVa^iOnS^ndiCate that Part
th® variation in mean water
level near shore is a function of the incoming wave field. However these
3-80