Computational Analysis and Experimental Comparison Ben Anderson (University of Minnesota) Huiquing Yao (University of Hawaii) Advisor: Dr. Ian Robertson (University of Hawaii) HARP REU Program 8/3/2011

 Introduction  Computational Models  2D vs. 3D  Computational data comparison with experimental data  Conclusions and Recommendations

 A blocked tsunami wave under a slab can caused a large uplift force –– piers, harbors, and building floor slabspiers, harbors, and building floor slabs  As a tsunami wave approaches the shore, it transform into a turbulent bore –– Turbulence model Turbulence model

Example pier structure -- Ryan Takakura

Failure of new ferry dock caused by 2009 Samoa tsunami (Robertson, et al, 2010)

 Simulating tsunami waves with a dam break Plan drawing of wave flume -- Ryan Takakura

Slab and wall setup --Ryan Takakura Dam break swing gate Dam break flume

 - “The Effects of Tsunamis on Coastal Structures” Back

 Dimensions  Mesh Size  k-ε and k-ω SST  3D and 2D Comparison

5.7404m 6.286m Total length : m Gap : 0m 2D model extended to equate extra volume at the end of the flume

Area surrounding the slab and tank floor were designed with a smaller cell size Back

 k-ε ◦ based on model transport equations for the turbulence kinetic energy ( k ) and its dissipation rate ( ε )  k-ω SST ◦ based on model transport equations for the turbulence kinetic energy ( k ) and the specific dissipation rate ( ω ) ◦ “Shear-stress transport” (SST) accounts for the transport of the turbulent shear stress

-incorporates standing water

 k-ω SST has a more realistic bore and pressure results  Used k-ω SST for our simulations

 The biggest issue with the two dimension model is the air that gets trapped under the slab  3D may give a more realistic representation of what actually happens

 Chose to use 2D model  2D has a faster computational speed

 Software: OpenFoam  Focused on the maximum uplift force (N)  k-ω SST for all cases  2D  Graphs: 0 cm gap

 Load cell measured net load  Computational model only measured integral of the uplift load on the slab

Slab height : 10cm Upstream : 45cm Downstream: 2.5cm

 Recommend making mesh finer to eliminate variances due to mesh size  Extend fine mesh out in front of the slabmesh  Different cases use different mesh sizes  Try more simulations in 3D

 "This material is based upon work supported by the National Science Foundation under Grant No Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

 Christy Allison, Taylor Dizon, Deanna Quickle. “The Effects of Tsunamis on Coastal Structures” REU, University of Hawaii at Manoa, summer 2010  Ge, Ming. “Uplift Loading On Elevated Floor Slab Due To A Tsunami Bore.” Thesis for Master’s Degree, Dept of Civil Engineering, University of Hawaii at Manoa, December 2010  Robertson, Ian, et al. “Reconnaissance Following the September 29, 2009 Tsunami in Samoa.” Research Report, Dept of Civil Engineering, University of Hawaii at Manoa, January  Takakura, Ryan. “Reducing Tsunami Bore Uplift Forces By Providing A Breakaway Panel.” Thesis for Master’s Degree, Dept of Civil Engineering, University of Hawaii at Manoa, December 2010

Any Questions?