measure v (current-meter) at 0.2 and 0.8 of depth average v and multiply by (width * depth)
DESCRIPTION
Stream Cross-Section for Q. Measure V (current-meter) at 0.2 and 0.8 of depth Average V and multiply by (width * depth) Sum up across stream to get total Q = S (V i D i W i ). - PowerPoint PPT PresentationTRANSCRIPT
• Measure V (current-meter) at 0.2 and 0.8 of depth
• Average V and multiply by (width * depth)
• Sum up across stream to get total Q = (Vi Di Wi)
Stream Cross-Section for Q
Rating curve hysteresis loop in Zenne river (Lot), 15-16 July 2012 event: blue triangles – rising stage, green squares – falling stage
CR
k s 1 1 2
ln
Flume tests carefully conducted by Nomicos (1957) at CalTech:
constant-depth, unique sediment size d=0.152mm
difficult to reconcile with the standard formulation for the ‘alluvial resistance coefficient’:
.
Bed-material discharge
Bed morphology adaptation
Alluvial resistance
Buoyancy-affected turbulence
10
32Sc
mU
BF
BF Dgcwith
2
tanh2
1m
Rdetached x
Umf 2
2 detachedfS
)1( m
If BF is the wavelength from crest to crest, the celerity of the associated gravity wave is given by Airy’s law:
BF
Dgc
BF
2tanh
2
BF
BF
Dg
BFattachedf
2tanh
2
1 attachedfS
1
2
attached
detached
f
fS
BF
Dg
UmS
BF
2tanh
2
2
310
detached
attached
f
fS
Facteur m
m = 1,1 m = 1,2
10
32Sc
mU
BF
BF Dgcwith
2
tanh2
1m
Discontinuity rating curve
original discontinuity rating curve Modified discontinuity rating curve
