Numerical Simulation of Surface Waves Generated by a Subaerial Landslide at Lituya Bay, Alaska

Abstract

This paper presents preliminary results of a computational study conducted to analyze the impulse waves generated by the subaerial landslide at Lituya Bay, Alaska. The volume of fluid (VOF) method is used to track the free surface and shoreline movements. The Renormalization Group (RNG) turbulence model and Detached Eddy Simulation (DES) multiscale model were used to simulate turbulence dissipation. The subaerial landslide is simulated using a sliding mass. Results from the two-dimensional (2-D) simulations are compared with results from a scaled-down experiment. The experiment is carried out at a 1:675 scale. In the experimental setup, the subaerial rockslide impact into the Gilbert Inlet, wave generation, propagation, and runup on the headland slope are considered in a geometrically undistorted Froude similarity model. The rockslide is simulated by a granular material driven by a pneumatic acceleration mechanism so that the impact characteristics can be controlled. Simulations are performed for different values of the landslide density to estimate the influence of slide deformation on the generated tsunami characteristics. Simulated results show the complex flow patterns in terms of the velocity field, shoreline evolution, and free surface profiles. The predicted wave runup height is in close agreement with both the observed wave runup height and that obtained from the scaled-down experimental model.