Bentuk bentuk kekasaran alluvial do
ALLUVIAL BEDFORMS AND ROUGHTNESS
Transport Sedimentation Paper
Lecturer: Dr. Very Dermawan, ST.,MT
Munfarid
Adam Wiguna
Reta Lilyananda Puspasari
Hana Arum Rossy Tamaya
Marianty Patabang
Danang Kiswanto
Rifqi Muhammad Iqbal
Annida Lisyahadah
Ria Puspasari
Moh. Ali Mabrur
Ivan Dwi Prabowo
Ganisa Elsina Salamena
Yuvika Rega Siswanti
(135060400111035
(135060401111014
(135060401111016
(135060401111018
(135060401111022
(135060401111036
(135060401111038
(135060401111048
(135060401111058
(135060401111059
(135060401111066
(135060401111068
(135060407111027
Ministry of Education and Culture
Brawijaya University
Faculty of Engineering
Water Resources Engineering
Malang, Indonesia
2014
)
)
)
)
)
)
)
)
)
)
)
)
)
I. GENERAL
The basic form sediments which occur in alluvial channel flow rate related to
the flow regime. Flow regime, which is a form that affects the flow of the
layer configuration. The following classification shows the relationship
between flow velocity and sediment transport modes (sediment transport), the
concentration of the transported sediment and forms the basis of the
relationship between phase and water (surface water).
Flow regime can be related to the Froude number characterizes whether flow
will be calm or fast. Froude number is an expression of the ratio between the
inertia (the force needed to stop the moving particles) and gravity.
F 1 rapid flow (upper flow regime)
In general, the basic shape of the flow regime, sediment is classified into:
A. Regime low flow
B. Regime transition flow
C. Regime high flow
A. Regime Low Flow
(Froude number 1
3. Chute and Pools, occurs in the slope, velocity and sediment discharge
which are relatively large. The basic form is a hill - a large sediment
hill. The state of the flow in chute is supercritical or subcritical.
I. Bedform Forecast
Determining the criteria of bedform, approach used by the sediment
continuity equation as follows:
s
+
=0
description:
s = specific weight of bed material
y = height of bedform at x along the river
t = time
qs = sediment flow in a weight unity wide and time
The first limitation showed a decrease in the rate of sediment at the base, and
the second limit sediment transport shows the change in the change of the
distance x along the river. It turns out that both these limits gradually always
opposite in sign, when the base is formed
.
positive and
negative.
The image above shows the cross-sectional shape at time t and t + dt from the
bedform that moves downstream. In the upper part of the lower forms of the
basic situation which is a function of time, so
From this equation, seemingly that
negative.
positive, so that qs increases
continuously until it reaches its peak.
Exner (1925), assumed that:
qs = Ao. uo
Ao = constant
Uo = flow velocity near the base
By entering Ao and Uo into the sediment Equalition continuity before, then
obtained :
s
+ Ao
=0
In 1963, Kennedy introduced the relation between the wavelength L of a
change in the bedform of the Froude number
Results of Kennedy’s investigationed to the dominant wavelength of the form
- the bedform is:
Fr2 =
=
Specification:
Fr = Froude number
d = depth of flow
U = velocity of flow
k = 2π / L = wave number
L = wavelength
j = ᵟ / d = deceleration factor
ᵟ = distance which can lead to changes in local sediment flow deceleration and
change of pace near the base
The concept of "lag distance" was first proposed by Kennedy (1963) and is the
most important factor.
Pictured above is the theoretical curve obtained kennedy with entering data
into the equation the dominant wavelength (the relationship between Fr and
kd).
Seen in Fr2, greater than (1 / kd) tanh kd, and the kd
Transport Sedimentation Paper
Lecturer: Dr. Very Dermawan, ST.,MT
Munfarid
Adam Wiguna
Reta Lilyananda Puspasari
Hana Arum Rossy Tamaya
Marianty Patabang
Danang Kiswanto
Rifqi Muhammad Iqbal
Annida Lisyahadah
Ria Puspasari
Moh. Ali Mabrur
Ivan Dwi Prabowo
Ganisa Elsina Salamena
Yuvika Rega Siswanti
(135060400111035
(135060401111014
(135060401111016
(135060401111018
(135060401111022
(135060401111036
(135060401111038
(135060401111048
(135060401111058
(135060401111059
(135060401111066
(135060401111068
(135060407111027
Ministry of Education and Culture
Brawijaya University
Faculty of Engineering
Water Resources Engineering
Malang, Indonesia
2014
)
)
)
)
)
)
)
)
)
)
)
)
)
I. GENERAL
The basic form sediments which occur in alluvial channel flow rate related to
the flow regime. Flow regime, which is a form that affects the flow of the
layer configuration. The following classification shows the relationship
between flow velocity and sediment transport modes (sediment transport), the
concentration of the transported sediment and forms the basis of the
relationship between phase and water (surface water).
Flow regime can be related to the Froude number characterizes whether flow
will be calm or fast. Froude number is an expression of the ratio between the
inertia (the force needed to stop the moving particles) and gravity.
F 1 rapid flow (upper flow regime)
In general, the basic shape of the flow regime, sediment is classified into:
A. Regime low flow
B. Regime transition flow
C. Regime high flow
A. Regime Low Flow
(Froude number 1
3. Chute and Pools, occurs in the slope, velocity and sediment discharge
which are relatively large. The basic form is a hill - a large sediment
hill. The state of the flow in chute is supercritical or subcritical.
I. Bedform Forecast
Determining the criteria of bedform, approach used by the sediment
continuity equation as follows:
s
+
=0
description:
s = specific weight of bed material
y = height of bedform at x along the river
t = time
qs = sediment flow in a weight unity wide and time
The first limitation showed a decrease in the rate of sediment at the base, and
the second limit sediment transport shows the change in the change of the
distance x along the river. It turns out that both these limits gradually always
opposite in sign, when the base is formed
.
positive and
negative.
The image above shows the cross-sectional shape at time t and t + dt from the
bedform that moves downstream. In the upper part of the lower forms of the
basic situation which is a function of time, so
From this equation, seemingly that
negative.
positive, so that qs increases
continuously until it reaches its peak.
Exner (1925), assumed that:
qs = Ao. uo
Ao = constant
Uo = flow velocity near the base
By entering Ao and Uo into the sediment Equalition continuity before, then
obtained :
s
+ Ao
=0
In 1963, Kennedy introduced the relation between the wavelength L of a
change in the bedform of the Froude number
Results of Kennedy’s investigationed to the dominant wavelength of the form
- the bedform is:
Fr2 =
=
Specification:
Fr = Froude number
d = depth of flow
U = velocity of flow
k = 2π / L = wave number
L = wavelength
j = ᵟ / d = deceleration factor
ᵟ = distance which can lead to changes in local sediment flow deceleration and
change of pace near the base
The concept of "lag distance" was first proposed by Kennedy (1963) and is the
most important factor.
Pictured above is the theoretical curve obtained kennedy with entering data
into the equation the dominant wavelength (the relationship between Fr and
kd).
Seen in Fr2, greater than (1 / kd) tanh kd, and the kd