VALIDATION A TWO-PHASE NUMERICAL
SOLVER FOR SIMULATING HYDRAULIC BORE
INTERACTIONS WITH NEARSHORE
STRUCTURES
7TH International Tsunami Symposium
ISPRA 2016
Steven Douglas
Academic Supervisor: Dr. Ioan Nistor
September 12 - 15th, 2016
2Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
PRESENTATION OVERVIEW
PRESENTATION OVERVIEW
Introduction
Objectives
The Numerical Model
Results
Conclusions
RISK MITIGATION
PUBLIC
AWARENESS AND
EMERGENCY
PREPAREDNESS
Inundation maps
Early warning systems
Evacuation plans
STRATEGIC
MITIGATION
Land-use planning
Soft engineering
Hard engineering/Building codes
INTRODUCTION : MITIGATION OF TSUNAMI EFFECTS
INTRODUCTION: MITIGATION OF TSUNAMI EFFECTS
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Deficiencies in existing design guidelines:
• Ghobara et al. (2006) • Nistor et al. (2009)• Chock et al. (2011)• Yeh et al. (2013)
“A comprehensive update of tsunami provisions has not beenmade largely due to lack of adequate data” – Chock et al.(2011)
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
The Cascadia Subduction Zone
[The Camino, 2007]
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STUDY OBJECTIVES
STUDY OBJECTIVES
Short-term goals
• Provide analysis of the hydrodynamic loading process
• Investigate role of entrained-air in loading process
• Comparative analysis with SPH
• Validate recent tsunami design guidelines
• FEMA P646
• ASCE 7-16
• Investigate influence of flume geometry
• Investigate influence of bed condition (ℎ𝑑)
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
Reproduction of physical experiments (Al-Faesly et al., 2012) using a two-phase numerical model
Long-term goals
• Aid in the advancement of tsunami design guidelines
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THE NUMERICAL MODEL : INTERFOAM
THE NUMERICAL MODEL: INTERFOAM
Numerical details:• Two incompressible fluids (air/water)• Volume of fluid (VoF)• Reynolds-averaged with turbulence• Artificial interface compression• Dynamic time step• Finite volume discretization
𝜕𝛼
𝜕𝑡+ 𝛻 ∙ 𝐔𝛼 + 𝛻 ∙ 𝐔𝐜𝛼 1 − 𝛼 = 0
Phase fraction (𝛼)
𝜕𝜌𝐔
𝜕𝑡+ 𝛻 ∙ 𝜌𝐔𝐔 = −𝛻𝑝∗ + 𝛻 ∙ 𝜇𝑒𝑓𝑓𝛻𝐔 + 𝛻𝐔 ∙ 𝛻𝜇𝑒𝑓𝑓 − 𝒈 ∙ 𝒙𝛻𝜌 + 𝜎𝜅𝛻𝛼
𝛻 ∙ 𝐔 = 0 Conservation of massConservation of momentum
Transport equation for phase fraction
AIR
WATER
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
BORE-STRUCTURE INTERACTION: PHYSICAL EXPERIMENTS
(AL-FAESLY ET AL., 2012)
THE PHYSICAL EXPERIMENTS (AL-FAESLY ET AL., 2012)
WAVE GAUGES
• w/ structure
• w/out structure
Experimental data• 8 wave gauge (WG)• 10 pressure transducers (PT)• 1 6-DOF force gauge
Experimental setup• Unobstructed flow• Obstructed flow w/ square • Three ℎ𝑢:
• 0.55 m• 0.85 m• 1.15 m
6Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
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CALIBRATION OF NUMERICAL PARAMETERS
𝒉𝒖 (m)Computational
Mesh
No. Grid
Cells
Computational
Time
0.85 5x5x5 169,735 2.6 hours
0.85 3x3x3 785,809 9.47 hours
0.85 2x2x2 3,608,180 1.62 days
0.85 1.5x1.5x1.5 8,468,152 3.79 days
0.85 2x2x2 Refined 1 5,496,080 3.04 days
0.85 2x2x2 Refined 0.5 8,703,596 8.86 days
1.15 2x2x2 Refined 1 7,025,110 5.63 days
1.15 2x2x2 Refined 0.5 10,176,435 >20 days
𝒉𝒖 (m)Computational
MeshTurbulence Model
Computational
Time
0.85 2x2x2 Refined 1 𝑘 − 𝜖 3.04 days
0.85 2x2x2 Refined 1 RNG 𝑘 − 𝜖 3.97 days
0.85 2x2x2 Refined 1 𝑘 − 𝜔 SST 3.40 days
1.15 2x2x2 Refined 1 𝒌 − 𝝐 5.63 days
1.15 2x2x2 Refined 1 RNG 𝑘 − 𝜖 6.65 days
1.15 2x2x2 Refined 1 𝑘 − 𝜔 SST 5.91 days
1.15 2x2x2 Refined 1 Realizable 𝑘 − 𝜖 5.72 days
CALIBRATION OF NUMERICAL MODEL Mesh size
𝒉𝒖 (m)Computational
Mesh𝑪𝒐𝒎𝒂𝒙
Computational
Time
0.55 2x2x2 Refined 1 0.8 0.95 days
0.55 2x2x2 Refined 1 1.0 1.18 days
0.55 2x2x2 Refined 1 2.0 1.75 days
Mesh size calibration
Turbulence model calibration
Maximum Courant Number calibration
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
VIDEO: NUMERICAL SIMULATION, ℎ𝑢=1.15m, SQUARE STRUCTURE
8Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
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MODEL VALIDATION: UNOBSTRUCTED FLOW
TIME: 0.75 SEC
TIME: 1.0 SEC
TIME: 1.25 SEC
MODEL VALIDATION: BORE PROFILES AND WATER LEVELS
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
10Numerical Modeling of Extreme Hydrodynamic Loading and Pneumatic Long Wave Generation
DEVELOPMENT OF PRESSURES AND FORCES
TIME: 1.05 secTIME: 1.9 secTIME: 2.35 secTIME: 3.6 secTIME: 7.0 sec
Impulsive ForcePeak SplashCollapse ForcePeak Hydrodynamic ForcePost-Peak Hydrodynamic
EXPERIMENTAL
NUMERICAL
Force t-history
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COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS
COMPARISON TO EXP. AND SPH RESULTS: FORCE TIME-HISTORY
ℎ𝑢 = 0.55 m
ℎ𝑢 = 1.15 m
ℎ𝑢 = 0.85 m
• Better agreement as ℎ𝑢(impulsive and hydrodynamic)
• Runup collapse force overestimated as ℎ𝑢(incompressible air)
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
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INFLUENCE OF BED CONDITION
Influence of ℎ𝑑:• ℎ𝑑 = 0mm• ℎ𝑑 = 5mm• ℎ𝑑 = 20mm• ℎ𝑑 = 50mm
INFLUENCE OF BED CONDITION
As ℎ𝑑 increases:• Reduction in bore-front celerity• Increase in bore-front depth• Change in impulsive and hydrodynamic load
FORCE TIME-HISTORY
BORE PROFILES
ℎ𝑑 = 0mmTIME: 1.35 seconds
ℎ𝑑 = 20mmTIME: 1.35 seconds
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
Compressibility of air seems to have little to no dampening effect of the experimental impulsive load.
Compressibility of air has substantial influence on the magnitude of the collapse force.
Both InterFoam and SPH performed well to reproduce the physical interactions between the bore and structure. Alternative to SPH Riemann solver for controlling instabilities
Impulsive load can be the governing load for structures or structural components less than or equal to the bore-front depth. Not yet accounted for in existing or upcoming tsunami design guidelines
Good agreement observed between Chanson’s (2009) analytical and numerical bore profile.
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CONCLUSIONS
CONCLUDING REMARKS
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
QUESTIONS AND ANSWERS
THANK YOU!
QUESTIONS?
[REUTERS KYODO, 2011]
14Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
ARTICLES SUBMITTED TO REFEREED JOURNALS
[1] Douglas, S. and Nistor, I. (2014). On the effect of bed condition on the development of tsunami-induced loading on structures using OpenFOAM. Journal of Natural Hazards, 76, 1335-1356. DOI 10.1007/s11069-014-1552-2. (M.A.Sc. work).
ARTICLES SUBMITTED TO REFEREED CONFERENCE PROCEEDINGS
[3] Douglas, S., Nistor, I. and St-Germain, P. (2015). 3D multi-phase numerical modelling of tsunami-induced hydrodynamic loading on nearshore structures. 36th IAHR World Congress, The Hague, Netherlands, June 28 – July 3, 2015. (M.A.Sc. work).
[4] Douglas, S. and Nistor, I. (2016). Multiphase numerical model for predicting bore-induced loading on structures. 35th ICCE, Istanbul, Turkey, July 17 – July 22, 2016. (Abstract submitted September 29, 2015, Submission ID: 1267). (M.A.Sc. work).
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PUBLICATIONS
PUBLICATIONS
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
Al-Faesly, T., Palermo, D., Nistor, I. and Cornett, A. (2012). Experimental modeling of extreme hydrodynamic forces on structural models, International Journal of Protective Structures (IJPS), 3(4), 477-505.
Árnason, H. (2005). Interactions between an incident bore and a free-standing coastal structure. Doctoral dissertation, Univ. of Washington, Seattle, WA.
Chan, I. and Liu, P.L. (2012). On the runup of long waves on a plane beach. Journal of Geophysical Research, 117, 1-17.
Chanson, H. (2006). Tsunami surges on dry coastal plains: application of dam break equations, Coastal Engineering Journal, Japanese Society of Civil Engineers (JSCE), 48(4), 355-370.
Chanson, H. (2009). Application of the method of characteristics to the dam break wave problem. Journal of Hydraulic Research, 47 (1), 41-49.
Chinnarasri, C., Thanasisathit, N., Ruangrassamee, A., Weesakul, S. and Lukkunaprasit, P. (2013). The impact of tsunami-induced bores on buildings. Proceedings of the Institution of Civil Engineering (ICE), Maritime Engineering, 166, 14-24.
Chock, G., Carden, L., Robertson, I., Olsen, M., and Yu, G. (2013). Tohoku tsunami-induced building failure analysis with implications for U.S. tsunami and seismic design codes. Earthquake Spectra, 29(1), 99-126.
FEMA P646. (2012). Guidelines for design of structures for vertical evacuation from tsunamis. Federal Emergency Management Agency, Washington, D.C.
Ghobarah, A., Saatcioglu, M. and Nistor, I. (2006). The impact of the 26 December 2004 earthquake and tsunami on structures and infrastructure. Engineering Structures, 28 (2), 312-326.
Goseberg, N., Wurpts, A. and Schlurmass, T. (2013). Laboratory-scale generation of tsunami and long waves. Coastal Engineering, 79, 57-74.
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REFERENCES
REFERENCES
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
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REFERENCESLinton, D., Gupta, R., Cox, D., Lindt, J., Oshnack, M. and Clauson, M. (2013). Evaluation of tsunami loads on
wood-frame walls at full scale. J. Structural Engineering, 139 (8), 1318-1325.
Lukkunaprasit, P., Thanasisathit, N. and Yeh, H. (2009). Experimental verification of FEMA P646 tsunami loading. Journal of Disaster Research, 4(6), 410-418.
Nistor, I., Palermo, D., Nouri, Y., Murty, T. and Saatcioglu, M. (2009). Tsunami forces on structures. In Kim, Y. C., Handbook of Coastal and Ocean Engineering, World Scientific, pp. 261-286.
Nouri, Y., Nistor, I. and Palermo, D. (2010). Experimental investigation of tsunami impact on free standing structures, Coastal Engineering Journal, JSCE, 52(1), 43-70.
Ramsden, J.D. (1993). Tsunamis: forces on a vertical wall caused by long waves, bores, and surges on a dry bed. Ph.D. thesis, California Institute of Technology, Pasadena, California.
Robertson, I.N., Riggs, H.R., Paczkowski, K. and Mohamed, A. (2011). Tsunami bore forces on walls. 30th
International Conference on Ocean, Offshore and Arctic Engineering, Rotterdam, the Netherlands, June 19-24, 2011.
Rossetto, T., Allsop, W., Charvet, I., and Robinson, D.I. (2011). Physical modelling a tsunami using a new pneumatic wave generator. Coastal Engineering, 58, 517-527.
St-Germain, P., Nistor, I., Townsend, R. (2012) Numerical modeling of the impact with structures of tsunami bores propagating on dry and beds using the SPH method. International Journal of Protective Structures 3(2), 221–255.
Yeh, H., Sato, S. and Tajima, Y. (2013). The 11 March 2011 East Japan Earthquake and Tsunami: Tsunami effects on coastal infrastructure and buildings. Pure and Applied Geophysics, 170, 1019-1031.
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
REFERENCES
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INFLUENCE OF BED CONDITION
Influence of ℎ𝑑:• ℎ𝑑 = 0mm• ℎ𝑑 = 5mm• ℎ𝑑 = 20mm• ℎ𝑑 = 50mm
INFLUENCE OF BED CONDITION
As ℎ𝑑 increases:• Reduction in bore-front celerity• Increase in bore-front depth• Change in impulsive and hydrodynamic load
FORCE TIME-HISTORY
BORE PROFILES
ℎ𝑑 = 0mmTIME: 1.35 seconds
ℎ𝑑 = 20mmTIME: 1.35 seconds
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
DEVELOPMENT OF FORCES
FORCE
TIME-HISTORY
TIME: 1.05 sec
TIME: 1.9 sec
TIME: 2.35 sec
TIME: 3.6 sec
TIME: 7.0 sec
Impulsive
Collapse
Peak hydrodynamic
19Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
TIME-HISTORY OF VERTICAL PRESSURE DISTRIBUTION
PRESSURE: VERTICAL DISTRIBUTION
Leading edge
impacts column
Splash collapses
onto incoming flow
Peak hydrodynamic
forceWG9
Tends towards
hydrostatic pressure
TIME-HISTORY COLUMN RUNUP
20Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
21Numerical Modeling of Extreme Hydrodynamic Loading and Pneumatic Long Wave Generation
DEVELOPMENT OF PRESSURES AND FORCES
TIME: 1.05 secTIME: 1.9 secTIME: 2.35 secTIME: 3.6 secTIME: 7.0 sec
Impulsive ForcePeak SplashCollapse ForcePeak Hydrodynamic ForcePost-Peak Hydrodynamic
EXPERIMENTAL
NUMERICAL
22
CALIBRATION OF NUMERICAL PARAMETERS
CALIBRATION OF NUMERICAL MODEL: BORE-STRUCTURE INTERACTION
Wall functionTurbulence model
Mesh resolution
Max. Courant Number
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
kEpsilon kOmegaSST
RealizeableKE RNGkEpsilon
CALIBRATION OF NUMERICAL MODEL: BORE-STRUCTURE INTERACTION
CALIBRATION OF NUMERICAL PARAMETERS
WAKE FORMATION [TIME: 2 seconds]
22Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
kEpsilon kOmegaSST
RealizeableKE RNGkEpsilon
CALIBRATION OF NUMERICAL MODEL: BORE-STRUCTURE INTERACTION
CALIBRATION OF NUMERICAL PARAMETERS
WAKE FORMATION [TIME: 3 seconds]
23Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
(a) Time: 1.9 sec
(b) Time: 2.25 sec
(c) Time: 3.0 sec
(d) Time: 7.5 sec
EFFECT OF INTERFACE COMPRESSION
Interface compression on Interface compression off
24Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
(a) Time: 1.35 sec
(b) Time: 1.95 sec
(c) Time: 3.15 sec
(d) Time: 5.0 sec
EFFECT OF INTERFACE COMPRESSION
Interface compression on Interface compression off
25Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
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COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS
COMPARISON TO EXPERIMENTAL RESULTS: WSE TIME-HISTORIES
WG1 WG9
WG11 WG13
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
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Pressure time-histories
(ℎ𝑢 = 1.15m)
COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS
Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
FLOW SYMMETRY
28Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
Time: 3.5 sec
EFFECT OF CHANNEL WIDTH
WALL EFFECTS
29Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
Time: 3.5 sec
EFFECT OF CHANNEL WIDTH
WALL EFFECTS
30Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures
Time: 3.5 sec
EFFECT OF CHANNEL WIDTH
WALL EFFECTS
32Three-dimensional Multiphase Numerical Modelling of Bore Impacts on Structures