Numerical Modelling of Hydrodynamics and Morphodynamics at ...
Numerical Modelling of Hydrodynamics and Morphodynamics at ...
Numerical Modelling of Hydrodynamics and Morphodynamics at ...
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<strong>Numerical</strong> <strong>Modelling</strong> <strong>of</strong><br />
<strong>Hydrodynamics</strong> <strong>and</strong> <strong>Morphodynamics</strong><br />
<strong>at</strong> Port Stephens, NSW, Australia<br />
Angela Wenping Jiang<br />
PHD C<strong>and</strong>id<strong>at</strong>e
Objectives<br />
To determine the interrel<strong>at</strong>ed morphodynamics<br />
<strong>of</strong> flood-tide deltas <strong>and</strong> adjacent shorelines.<br />
‣ Dominant hydrodynamic y processes governing g flood-tide<br />
delta/shoreline morphodynamics;<br />
‣ Existing sediment transport p<strong>at</strong>hways <strong>and</strong> sediment<br />
budgets;<br />
‣ System response to extreme events;<br />
‣ System response to clim<strong>at</strong>e change driven vari<strong>at</strong>ions in<br />
environmental forcing parameters (e.g. Sea level rise).<br />
2
Study Site<br />
Port Stephens is classified as a tide-domin<strong>at</strong>ed domin<strong>at</strong>ed estuary th<strong>at</strong> is<br />
loc<strong>at</strong>edonawavedomin<strong>at</strong>ed on a wave-domin<strong>at</strong>ed coast.<br />
Flood-tide<br />
delta<br />
Port Stephens<br />
Port Stephens (photo courtesy <strong>of</strong> DECC)
Methods<br />
A process-based<br />
2DH<br />
numerical modelling approach<br />
Hydrodynamic<br />
Simul<strong>at</strong>ion<br />
(MIKE 21 HD)<br />
Wave Transform<strong>at</strong>ion<br />
<strong>and</strong> Calcul<strong>at</strong>ion<br />
(MIKE 21 SW)<br />
Sediment Transport<br />
Calcul<strong>at</strong>ion<br />
Erosion/Accretion<br />
4
Model Setup_ Mesh<br />
5
Calibr<strong>at</strong>ion <strong>and</strong> Valid<strong>at</strong>ion<br />
JB4<br />
JB2<br />
JB3<br />
JB1<br />
SB1<br />
Port Stephens (photo courtesy <strong>of</strong> DECC)<br />
SB2<br />
SB4<br />
SB3<br />
Tomaree<br />
6
Comparisons <strong>of</strong> Predictions <strong>and</strong><br />
Measurements - HD<br />
1<br />
0.5<br />
[m]<br />
0<br />
-0.5<br />
-1<br />
0.5<br />
0.4<br />
m/s<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
400<br />
300<br />
Deg gree<br />
200<br />
100<br />
0<br />
6/03/08 7/03/08 8/03/08 9/03/08 10/03/08<br />
W<strong>at</strong>er levels (above), current speeds (middle) <strong>and</strong> directions (below) <strong>at</strong><br />
JB3: measured (blue) <strong>and</strong> modelled (pink)<br />
7
St<strong>at</strong>istical Analyses<br />
RMS (m)<br />
RMS/max.<br />
Vari<strong>at</strong>ion<br />
Correl<strong>at</strong>ion<br />
Coefficient<br />
W<strong>at</strong>er 0.07-0.16 3.5-9.3% 0.97-0.98<br />
Level<br />
Current 004-0 0.04-0.0808 10.1-20.21-20 2 % 063-0 0.63-0.90<br />
Velocity<br />
Overall, good agreements between measurements <strong>and</strong><br />
model predictions have been achieved.<br />
8
Comparisons <strong>of</strong> Predictions <strong>and</strong><br />
Measurements - SW<br />
Hs [m]<br />
05 0.5<br />
0.4<br />
0.3<br />
<strong>at</strong> JB4:<br />
HMeasured 02 0.2<br />
(blue) <strong>and</strong><br />
0.1<br />
Significant wave height<br />
modelled (pink)<br />
0.0<br />
6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00<br />
04-04-2008<br />
0.6<br />
05 0.5<br />
0.4<br />
Significant wave height<br />
<strong>at</strong> SB4:<br />
Measured (blue) <strong>and</strong><br />
modelled (pink)<br />
Hs [m]<br />
0.3<br />
02 0.2<br />
0.1<br />
0<br />
7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00<br />
23-07-2008<br />
9
Model Applic<strong>at</strong>ions<br />
Model experiment<br />
Tides<br />
HD<br />
Wind<br />
Ocean<br />
waves<br />
SW<br />
Wind<br />
Tide only<br />
√<br />
Tide <strong>and</strong> wind<br />
shear<br />
Tide <strong>and</strong> ocean<br />
waves<br />
Tide, ocean <strong>and</strong><br />
local waves<br />
√<br />
√<br />
√<br />
√<br />
√ √ √<br />
* Average wave conditions: Hs=1.63 m, Tp=9.57 sec, predominant wave<br />
direction=SSE (Lord <strong>and</strong> Kulmar 2000)<br />
* Moder<strong>at</strong>e wind: southerly <strong>and</strong> westerly, speed=7.2 m/s<br />
10
Dominant hydrodynamic processes <strong>at</strong><br />
Jimmy’s Beach<br />
Zone1<br />
Zone2<br />
Zone3<br />
Zone4<br />
Zone5<br />
Zone6<br />
Zone7<br />
11
Results _ Tides<br />
12
Ocean Waves<br />
14
Ocean Waves<br />
15
Wind Waves<br />
16
Comparisons s <strong>of</strong> Peak Currents<br />
Mean currents during peak flood tide<br />
02 0.2<br />
0.1<br />
0<br />
-0.1<br />
0.3<br />
Zone1 Zone2 Zone3 Zone4 Zone5 Zone6 Zone7<br />
Mean currents during peak ebb tide<br />
0.2<br />
0.1<br />
0<br />
-0.1<br />
Zone1 Zone2 Zone3 Zone4 Zone5 Zone6 Zone7<br />
17
Wave Orbital Velocity<br />
1<br />
08 0.8<br />
m/s<br />
0.6<br />
0.4<br />
Particle_bed<br />
Particlel_surface<br />
0.2<br />
0<br />
Zone1 Zone2 Zone3 Zone4 Zone5 Zone6 Zone7<br />
18
Conclusions<br />
Flow p<strong>at</strong>terns along Jimmy’s Beach are<br />
sp<strong>at</strong>ially variable.<br />
Under SSE average wave <strong>and</strong> moder<strong>at</strong>e wind<br />
conditions:<br />
‣ Nearshore<br />
flows are domin<strong>at</strong>ed by<br />
ocean-wave<br />
<strong>and</strong> tidally<br />
induced<br />
flows.<br />
‣ Locally gener<strong>at</strong>ed wind waves <strong>and</strong><br />
wind shear appear to be rel<strong>at</strong>ively<br />
insignificant.<br />
19
Future Work<br />
‣The effects <strong>of</strong> storm events<br />
‣Sediment transport in swash zone<br />
20
Acknowledgements<br />
‣Australian Research Council<br />
‣NSW Department <strong>of</strong> Environment <strong>and</strong> Clim<strong>at</strong>e<br />
Change (DECC)<br />
‣Gre<strong>at</strong> Lakes Council<br />
‣Port Stephens Council<br />
‣Jimmy’s s Beach Restor<strong>at</strong>ion Society Inc.<br />
‣Manly Hydraulics Labor<strong>at</strong>ory (MHL)<br />
‣Australian Bureau <strong>of</strong> Meteorology (BOM)<br />
‣Field d<strong>at</strong>a processed by Tim Austin, Dan Harris <strong>and</strong><br />
Gen Pezzimenti.<br />
Thank you!