Environmental and Water Resources Engineering DivisionCivil Engineering

Dr. Soumendra Nath Kuiry

Assistant Professor

Hurricane Gustav (2008) Simulation by CCHE-Coast

Civil Engineering HPC Lecture

Model Description: CCHE-Coast

CCHE-Coast

3. Spectral-wave Model

1. Hydrodynamic Model

2. Hurricane Track Model

(Yafei Jia) (S. N. Kuiry) (Yan Ding)

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Civil Engineering HPC Lecture

Hurricane Gustav (2008) Track

Fig. 1: The track of hurricane Gustav (2008) by Weather Bug

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Civil Engineering HPC Lecture

Computational Domain

Fig. 2: Computational area selected for the present study is delimited by the red line

Longitudinal: 9137'27" W - 8740'18"W Transverse: 2834'35" N - 3046'27" N

Cocodrie, LALandfall Point

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Area: 440km 320km

Civil Engineering HPC Lecture

Computational Mesh

• The Study domain covers a large area (about 440 km 320 km).

• The major features include Rivers, Lakes, Levees, Roads, Protection structures and barrier islands.

• Block structured mesh were created using 17 blocks.

• Each block was controlled for certain resolution.

• The bathymetry was derived from SL15 mesh created by USACE.

• The mesh has 2103 and 1088 grid points in the longitudinal and latitudinal directions: about 2.29 million nodes.

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Fig. 3: (a) New Orleans storm protection System and (b) its implementation in the mesh

(a)

(b)

Civil Engineering HPC Lecture

Mississippi River

Atchafalaya River

Bathymetry and Mesh

Fig. 4: The bathymetry and the mesh consisting of 2,288,064 nodes

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Civil Engineering HPC Lecture

Details of New Orleans City, Structures and Rivers

Fig. 5: Enlarged view showing the details of the final mesh area around Lake Pontchartrain and the Pearl River.

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Civil Engineering HPC Lecture

Bottom Friction

Fig. 6: Manning’s roughness coefficient

Roughness coefficients are obtained from land use and land cover map of the area provided by USACE. In the extended area a constant value 0.02 is considered.

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Civil Engineering HPC Lecture

Input Parameters

• Storm Track – best track observed by NOAA

• Tides - the observed tidal elevations at the Pilots Station East, SW Pass, LA is used as the tidal boundary condition at the south open sea boundary.

• Waves – the observed wave data from NDBC is applied at the sea boundary.

• River inflows - The stream gages USGS 07374000 on Mississippi River at Baton Rouge, LA and USGS 07381490 on Atchafalaya River at Simmesport, LA provided the inflow discharges during Hurricane Gustav (2008).

• Simulation period - from 08/25/2008 0:0 hrs – 09/03/2008 0:0 hrs.

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Civil Engineering HPC Lecture

Boundary Conditions

Mississippi River

Atchafalaya River

8/15 8/18 8/21 8/24 8/27 8/30 9/2-0.2-0.1

00.10.20.30.40.50.60.7

Time (days)

Wat

er s

urfa

ce e

leva

tion

(m)

8/15 8/18 8/21 8/24 8/27 8/30 9/26000

7000

8000

9000

10000

11000

12000

13000

Time (days)

Dis

char

ge (m

3/s)

8/15 8/18 8/21 8/24 8/27 8/30 9/2200025003000350040004500500055006000

Time (days)

Dis

char

ge (m

3/s)

Fig. 7: The river inflows and tide at the sea boundary imposed as boundary conditions

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Civil Engineering HPC Lecture

Computational Challenges

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• Domain size• Mesh Generation• Model run• Visualization of Results

Civil Engineering HPC Lecture

Results and Discussions

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Civil Engineering HPC Lecture

Location and Index of Stations

Fig. 8: The location of observation stations for comparative study

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Civil Engineering HPC Lecture

Comparison of Water Surface ElevationsNOAA 8735180 Dauphin Island, AL NOAA 8737048 Mobile State Docks, AL NOAA 8741533 Pascagoula NOAA Lab, MS

NOAA 8760922 Pilots Station East, LA NOAA 8747437 Bay Waveland Yacht Club, MS NOAA 8762075 Port Fourchon, LA

Fig. 9: Time series of computed and observed water surface elevations

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Civil Engineering HPC Lecture

Maximum Water Surface Elevations

(b)

Fig. 10: Computed maximum water surface elevation above NAVD88: (a) Forbes et al. (2010) and (b) present simulation

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Civil Engineering HPC Lecture

Animation: Water Surface Elevations

Fig. 11: Animation of water surface elevation (01/09/08 0:0 hrs – 02/09/08 0:0 hrs)

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Civil Engineering HPC Lecture

Wave Parameters

Fig. 12: Comparisons: (a) significant wave height and (b) mean wave period

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(a) (b)

NDBC 42040 Luke Offshore Test Platform

(a) (b)

NDBC 42007 Biloxi station

Civil Engineering HPC Lecture

Wind Speed Comparison

8/28 8/29 8/30 8/31 9/1 9/20

10

20

30

40NDBC 42040 Luke offshore Test Platform, AL

Win

d S

peed

(m

/s)

8/28 8/29 8/30 8/31 9/1 9/20

10

20

30

40NDBC 42007 Biloxi, MS

Win

d S

peed

(m

/s)

8/28 8/29 8/30 8/31 9/1 9/20

10

20

30

40NOAA 8735180 Dauphin Island, AL

Win

d S

peed

(m

/s)

8/28 8/29 8/30 8/31 9/1 9/20

10

20

30

40

50NOAA 8761927 New Canal Station, LA

Time (days)

Win

d S

peed

(m

/s)

Fig. 13: Time series of computed and observed wind speeds at different stations

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10

20

30

40

50NOAA 8760922 Pilots Station East, LA

Time (days)

Win

d S

peed

(m

/s)

8/28 8/29 8/30 8/31 9/1 9/20

10

20

30

40

50NOAA 8761305 Shell Beach, LA

Time (days)

Win

d S

peed

(m

/s)

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Civil Engineering HPC Lecture

Wind Direction Comparison

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90

180

270

360NDBC 42040 Luke Offshore Test Platform, AL

Deg

rees

8/30 8/31 9/1 9/20

90

180

270

360NDBC 42007 Biloxi, MS

Deg

rees

8/30 8/31 9/1 9/20

90

180

270

360NOAA 8735180 Dauphin Island, AL

Deg

rees

8/30 8/31 9/1 9/20

90

180

270

360NOAA 8761927 New Canal Station, LA

Time (days)

Deg

rees

Fig. 14: Time series of computed and observed wind directions at different stations

8/30 8/31 9/1 9/20

90

180

270

360NOAA 8760922 Pilots Station East, LA

Time (days)

Deg

rees

8/30 8/31 9/1 9/20

90

180

270

360NOAA 8761305 Shell Beach, LA

Time (days)

Deg

rees

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Civil Engineering HPC Lecture

Computed Wind Field

Fig. 15: Computed wind field on 1 Sep 2008 at 7:50 hrs

Fig. 16: Computed wind field on 1 Sep 2008 at 16:00 hrs

Fig. 17: Wind field animation (01/09/08 0:0 hrs – 02/09/08 0:0 hrs)

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Civil Engineering HPC Lecture

Computed Air Pressure Field

Fig. 18: Computed air pressure fields on 1 Sep 2008 at 7:50 hrs

Fig. 19: Computed air pressure fields on 1 Sep 2008 at 16:16 hrs

Fig. 20: Air pressure field animation (01/09/08 0:0 hrs – 02/09/08 0:0 hrs)

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Civil Engineering HPC Lecture

Computational Resources

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Multi-cores (more than 12)

NVIDIA graphic card for GPU operations

Tecplot software in the high speed computer

A Wiki of subroutines for known algorithms

Video tutorials for large scale computations