Leverage CFD to Predict, Model, and Mitigate Tsunamis for a Safer Tomorrow

20 Apr 2023 • 6 minute read

Severe heatwaves, frequent droughts, floods, melting ice caps, and warm oceans with acidic waters are all signs of climate change and its drastic impact. It’s not our planet’s first time; Earth has experienced these glacial and inter-glacial periods every 100,000-year cycle in the last 1 million years. So, we rest assured that Earth will survive, and evolutionary changes will follow, but what qualms us is that climate change might wipe off mankind and disturb the ecosystem. Predicting and modeling a few outcomes of climate change using advanced simulation tools can be a positive stride against climate change. Here we elaborate on how computational fluid dynamic (CFD) tools can help predict and model the generation, propagation, and mitigation of tsunamis for a safer tomorrow, especially targeting the safety of the inhabitants and building clusters around the coastal regions.

Propagation of Tsunami Waves

How are Tsunamis an Outcome of Climate Change?

A predominant climate change variable is surface water which could be snow or rainwater. As temperature rises, frozen soil at high altitudes starts melting, resulting in aerial and submarine landslides, eventually forming tsunamis. One of the largest tsunamis recorded in the world was in Alaska due to the melting of permafrost or frozen soil, causing a landslide that sent 180 million tonnes of rocks into a fjord (U-shaped valley), resulting in a 193 m high tsunami. According to a study in Macau, China, a 50 cm rise in sea level will double the frequency of tsunami-induced flooding. Large, shallow earthquakes that pass through a seafloor or ocean floor can also lead to tsunamis. These tsunamis are indirectly the aftermath of climate change.

Impact created by an Asteroid

Tsunamis can also be formed when a bolide body hits the Earth’s surface. For example, the Chicxulub tsunami occurred 66 million years ago, when a Chicxulub asteroid hit the Earth’s surface near the Yucatan peninsula. It was noted that this global tsunami was about 30,000 times stronger than any modern-day tsunami. The mass extinction of the Cretaceous Paleogene era is directed toward this massive tsunami. To understand the Chicxulub impact tsunami better, a group of researchers from the University of Michigan used a hydrocode to simulate and study the displacement of water and sediment over the first 10 mins after it started. The results from the study, i.e., the upper cretaceous marine sediment distribution, were consistent with the model results and confirm that these simulation studies are a breakthrough for tsunami prediction.

CFD Simulation for Tsunami Modeling

Before CFD came into the picture, many tsunami studies used 2D and 3D experiments to evaluate the governing factors and their impacts. Later based on these studies, numerical models were developed. In 2019, Kim and his researchers developed a numerical model TSUNAMI3D based on Navier Stokes equations and the volume of fluid method. This model was validated by comparing the results with a set of subaerial landslide experiments. Such numerical models provide grounds for understanding and generating complex non-linear wave propagation.

The need for advanced tsunami models and simulation techniques was felt profusely with the failure of the wall designed to protect the coasts of Tohoku in Japan. The impact of a tsunami on the surroundings and possible sustainable protection solutions can be investigated using the CFD simulation results. Tsunami modeling using high-fidelity turbulence models such as large eddy simulation (LES) can provide a more profound understanding of tsunami risk and inland propagation. Moreover, these simulations can also provide insights into the resistance capabilities of various tsunami protection solutions. From a few CFD studies, it was noted that vegetation, topography, and coastal geomorphology have an impact on the extent of tsunami propagation.

Tsunami Modeling Using Fidelity Fine Marine

CFD simulation is largely used in geophysics and ocean wave studies for its versatility, accuracy, and turnaround time. Since climate change has become the talk of the hour, CFD finds its space in landslide and tsunami modeling. Cadence Fidelity Fine Marine can generate hydrodynamic flow simulations of tsunami wave height and their corresponding effects on coastal building clusters. These simulations are based on Reynolds-averaged Navier-Stokes equations using turbulence models at full tsunami scale with wave breaking. Understanding the impacts allows the development of various strategies to reduce casualties: