Shallow water simulations on complex ocean domains using block-structured grids

Titelangaben

Faghih-Naini, Sara ; Zint, Daniel ; Kuckuk, Sebastian ; Kemmler, Samuel ; Aizinger, Vadym ; Grosso, Roberto ; Köstler, Harald:
Shallow water simulations on complex ocean domains using block-structured grids.
2022
Veranstaltung: Platform for Advanced Scientific Computing (PASC) Conference 2022 , 27.-29. June 2022 , Basel, Switzerland.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Poster )

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Abstract

Real-world ocean domains often have complex geometry and topography and are thus best suited for unstructured-mesh discretizations. However, structured grids offer performance advantages on cache-based architectures due to regular memory accesses. To combine the geometrical flexibility of unstructured meshes with the performance benefits of structured ones, we developed a block-structured grid generator for realistic ocean domains. In order to be able to represent correctly small features such as small islands and narrow channels, we enhance our methodology by allowing the generated grids to cover a larger area than the actual computational domain and introduce masking to exclude excessive grid elements.
The automatically generated block-structured grids are used for simulations with GHODDESS, a code generation framework based on ExaStencils which discretizes the shallow water equations by a quadrature-free discontinuous Galerkin method.
A key feature of the grid generation with regard to high performance computing is the ability to exactly specify a required number of blocks, i.e. load imbalances can be avoided. We validate our approach by comparing the simulation results on unstructured and masked block-structured grids for complex ocean domains and present performance studies for our new methodology.