ESTIMATION OF HYDRAULIC PARAMETERS OF ARMORED LAYER FORMING IN MOUNTAIN RIVERS AND STREAMS
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ESTIMATION OF HYDRAULIC PARAMETERS OF ARMORED LAYER FORMING IN MOUNTAIN RIVERS AND STREAMS Wojciech Bartnik, Andrzej Strużyński Krakow Agriculture University
description
ESTIMATION OF HYDRAULIC PARAMETERS OF ARMORED LAYER FORMING IN MOUNTAIN RIVERS AND STREAMS. Wojciech Bartnik, Andrzej Strużyński. Krakow Agriculture University. PLAN. Introduction Bed load Characteristics of bed load Field and laboratory measurements - PowerPoint PPT Presentation
Transcript of ESTIMATION OF HYDRAULIC PARAMETERS OF ARMORED LAYER FORMING IN MOUNTAIN RIVERS AND STREAMS
ESTIMATION OF HYDRAULIC PARAMETERS OF ARMORED LAYER FORMINGIN MOUNTAIN RIVERS AND STREAMS
Wojciech Bartnik, Andrzej Strużyński
Krakow Agriculture University
PLAN
Introduction Bed load Characteristics of bed load Field and laboratory measurements Velocity profile during change of bed
parameters Conclusions
INTRODUCTION
Hydraulic parameters of armored layer forming can be described on basis of stochastic nature of bed load movement proposed by Gessler.
The purpose of laboratory experiment was to describe the change of velocity profile and basic hydraulic parameters during armoring process.
BED LOAD
Stochastic nature of grain movement – turbulence ...
BED LOAD
Stochastic nature of grain movement – loops, sweeps ...
BED LOAD
q p c 0 /
Gessler’s function
max
min0
min0
)()(
)()(
)( d
d
di
da
dipdiq
dipdiq
dip
BED LOAD
Shields curve, Wang’s equation, Bartnik’s modification
c i s if g d
f f d di m i m
r/ /
FIELD MEASUREMENTS
Tenczyński Stream
FIELD MEASUREMENTS
Tenczyński Stream
FIELD MEASUREMENTS
Tenczyński Stream
FIELD MEASUREMENTS
Tenczyński Stream
FIELD MEASUREMENTS
Krzczonowski Stream – upper part
FIELD MEASUREMENTS
Krzczonowski Stream
FIELD MEASUREMENTS
Krzczonowski Stream
LABORATORY MEASUREMENTS
Flume dimensions: l2.0 x 0.5 x 0.6 m (glass walls)
Flume rig: micro-propeller flow-meter slope measurements
Bed slope, water surface slope Discharge: max 0.13 qm s-1 Trap for bed load Artificial grains Ø – 4 to 8 cm
LABORATORY MEASUREMENTS
artificial and natural grains
LABORATORY MEASUREMENTS
artificial and natural grains
BED ROUGHNESS
artificial and natural grains
N
n n Hhn
K1
2
1
1
Profile-meter AG-1
BED ROUGHNESS
comparing roughness with K
BED ROUGHNESS
observation of critical stresses
VELOCITY PROFILE DURINGCHANGE OF BED PARAMETERS
bed load transport influences roughness (K)
VELOCITY PROFILE DURINGCHANGE OF BED PARAMETERS
U/Umax = A log (y/Y) + B
B becomes constant - B = 1.12 ± 3%
A = 39.3 K + 0.24
A = 6.38 (Y/K)-0.835
VELOCITY PROFILE DURINGCHANGE OF BED PARAMETERS
U/Umax = A log (y/Y) + B
CONCLUSIONS
The interaction between bed load and flowing water creates the actual flow parameters. Bed roughness acts on flowing water more significantly after armouring process. Small fractions hidden and packed in bigger ones make bed roughness smaller.
During flood after uncovering armour coat mass transport appear due to even higher bed velocity. Scouring process grows stronger then before. After flood accumulation zones appear and river flow direction changes due to flow concentration.
