Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/nhess-2018-150
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
01 Jun 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Natural Hazards and Earth System Sciences (NHESS).
A comparison of a two-dimensional depth averaged flow model and a three-dimensional RANS model for predicting tsunami inundation and fluid forces
Xinsheng Qin1, Michael Motley1, Randall LeVeque2, Frank Gonzalez3, and Kaspar Mueller4 1Department of Civil and Environmental Engineering, University of Washington, More Hall Box 352700, Seattle, WA 98195
2Department of Applied Mathematics, University of Washington, Seattle, WA 98195
3Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195
4School of Computer Science and Communication, KTH, Royal Institute of Technology, 100 44 Stockholm, Sweden
Abstract. The numerical modeling of tsunami inundation that incorporates the built environment of coastal communities is challenging for both depth-integrated 2D and 3D models, not only in modeling the flow, but also in predicting forces on coastal structures. For depth-integrated 2D models, inundation and flooding in this region can be very complex with variation in the vertical direction caused by wave breaking on shore and interactions with the built environment and the model may not be able to produce enough detail. For 3D models, a very fine mesh is required to properly capture the physics, dramatically increasing the computational cost and rendering impractical the modeling of some problems. In this paper, comparisons are made between GeoClaw, a depth-integrated 2D model based on the nonlinear shallow water equations (NSWE), and OpenFOAM, a 3D model based on Reynolds Averaged Navier-Stokes (RANS) equation for tsunami inundation modeling. The two models were first validated against existing experimental data of a bore impinging onto a single square column. Then they were used to simulate tsunami inundation of a physical model of Seaside, Oregon. The resulting flow parameters from the models are compared and discussed, and these results are used to extrapolate tsunami-induced force predictions. It was found that the 2D model did not accurately capture the important details of the flow near initial impact due to the transiency and large vertical variation of the flow. Tuning the drag coefficient of the 2D model worked well to predict tsunami forces on structures in simple cases but this approach was not always reliable in complicated cases. The 3D model was able to capture transient characteristic of the flow, but at a much higher computational cost; it was found this cost can be alleviated by subdividing the region into reasonably sized subdomains without loss of accuracy in critical regions.
Citation: Qin, X., Motley, M., LeVeque, R., Gonzalez, F., and Mueller, K.: A comparison of a two-dimensional depth averaged flow model and a three-dimensional RANS model for predicting tsunami inundation and fluid forces, Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2018-150, in review, 2018.
Xinsheng Qin et al.
Xinsheng Qin et al.
Xinsheng Qin et al.

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Short summary
This manuscript presents the comparison of two numerical models, which model tsunami inundation that incorporates the built environment of coastal communities. It was found that the 2D model did not accurately capture the important details of the flow near initial impact due to the transiency and large vertical variation of the flow. The 3D model was able to capture transient characteristic of the flow, but at a much higher computational cost.
This manuscript presents the comparison of two numerical models, which model tsunami inundation...
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