A new computational framework for multi‐scale ocean modelling based on adapting unstructured meshes

Piggott, Matthew D.; Gorman, Gerard J.; Pain, Christopher C.; Allison, Peter A.; Candy, Adam S.; Martin, B. T.; Wells, M. J.

doi:10.1002/fld.1663

Cited by 156 publications

(135 citation statements)

References 16 publications

Supporting

Mentioning

135

Contrasting

Order By: Relevance

“…The model is based upon the fluid dynamics code Fluidity (Piggott et al, 2008), which solves the Navier-Stokes equations on a fully unstructured three-dimensional finite element mesh. The model formulation builds upon the work of Kimura et al (2013), with the addition of a large eddy simulation (LES) turbulence model (Smagorinsky, 1963) and the use of the synthetic eddy method (SEM) at the inlet (Jarrin et al, 2006).…”

Section: Plume Model and Submarine Melt Ratesmentioning

confidence: 99%

Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard

et al. 2018

View full text Add to dashboard Cite

Abstract. In this paper, we study the effects of basal friction, sub-aqueous undercutting and glacier geometry on the calving process by combining six different models in an offlinecoupled workflow: a continuum-mechanical ice flow model (Elmer/Ice), a climatic mass balance model, a simple subglacial hydrology model, a plume model, an undercutting model and a discrete particle model to investigate fracture dynamics (Helsinki Discrete Element Model, HiDEM). We demonstrate the feasibility of reproducing the observed calving retreat at the front of Kronebreen, a tidewater glacier in Svalbard, during a melt season by using the output from the first five models as input to HiDEM. Basal sliding and glacier motion are addressed using Elmer/Ice, while calving is modelled by HiDEM. A hydrology model calculates subglacial drainage paths and indicates two main outlets with different discharges. Depending on the discharge, the plume model computes frontal melt rates, which are iteratively projected to the actual front of the glacier at subglacial discharge locations. This produces undercutting of different sizes, as melt is concentrated close to the surface for high discharge and is more diffuse for low discharge. By testing different configurations, we show that undercutting plays a key role in glacier retreat and is necessary to reproduce observed retreat in the vicinity of the discharge locations during the melting season. Calving rates are also influenced by basal friction, through its effects on near-terminus strain rates and ice velocity.

show abstract

Section: Plume Model and Submarine Melt Ratesmentioning

confidence: 99%

Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard

et al. 2018

View full text Add to dashboard Cite

show abstract

“…There exist standards already that tackle these challenges well. It is rather a new problem descriptor, like those for Fluidity (Piggott et al, 2008) and the TerraFERMA model of Wilson et al (2017), for fully describing the mesh generation problem specifically for geophysical model domains, following the approach that this requires solving the same types of challenges involved in numerical model set-up, which makes significant progress in meeting the tenets of Table 1.…”

Section: Discussionmentioning

confidence: 99%

Shingle 2.0: generalising self-consistent and automated domain discretisation for multi-scale geophysical models

Candy

Pietrzak

2018

Geosci. Model Dev.

View full text Add to dashboard Cite

Abstract. The approaches taken to describe and develop spatial discretisations of the domains required for geophysical simulation models are commonly ad hoc, model-or application-specific, and under-documented. This is particularly acute for simulation models that are flexible in their use of multi-scale, anisotropic, fully unstructured meshes where a relatively large number of heterogeneous parameters are required to constrain their full description. As a consequence, it can be difficult to reproduce simulations, to ensure a provenance in model data handling and initialisation, and a challenge to conduct model intercomparisons rigorously. This paper takes a novel approach to spatial discretisation, considering it much like a numerical simulation model problem of its own. It introduces a generalised, extensible, selfdocumenting approach to carefully describe, and necessarily fully, the constraints over the heterogeneous parameter space that determine how a domain is spatially discretised. This additionally provides a method to accurately record these constraints, using high-level natural language based abstractions that enable full accounts of provenance, sharing, and distribution. Together with this description, a generalised consistent approach to unstructured mesh generation for geophysical models is developed that is automated, robust and repeatable, quick-to-draft, rigorously verified, and consistent with the source data throughout. This interprets the description above to execute a self-consistent spatial discretisation process, which is automatically validated to expected discrete characteristics and metrics.Library code, verification tests, and examples available in the repository at https://github.com/shingleproject/ Shingle. Further details of the project presented at http:// shingleproject.org.

show abstract

“…For further comparison, the performance of the Navier-Stokes model is compared against an existing finite element code. Fluidity is a multi-purpose finite element CFD code with a diverse range of applications (see, for example, Piggott et al [61] and Davies et al [62]). Although a continuous adjoint model has previously been derived by hand [63,64], this is no longer available.…”

Section: Incompressible Navier-stokesmentioning

confidence: 99%

Rapid development and adjoining of transient finite element models

Maddison

Farrell

2014

Computer Methods in Applied Mechanics and Engineering

View full text Add to dashboard Cite

Recent advances in high level finite element systems have allowed for the symbolic representation of discretisations and their efficient automated implementation as model source code. This allows for the extremely compact implementation of complex non-linear models in a handful of lines of high level code. In this work we extend the high level finite element FEniCS system to introduce an abstract representation of the temporal discretisation: this enables the similarly rapid development of transient finite element models. Efficiency is achieved via aggressive optimisations that exploit the temporal structure, such as automated pre-assembly and caching of forms, and the robust re-use of matrix factorisations and preconditioner data. The resulting models are as fast or faster than hand-optimised finite element codes. The high level representation of the system remains extremely compact and easily manipulated. This structure is exploited to derive the associated discrete adjoint model automatically, with the adjoint model inheriting the performance advantages of the forward model. Combined, this provides a system for the rapid development of efficient transient models, together with their discrete adjoints.

show abstract

A new computational framework for multi‐scale ocean modelling based on adapting unstructured meshes

Cited by 156 publications

References 16 publications

Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard

Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard

Shingle 2.0: generalising self-consistent and automated domain discretisation for multi-scale geophysical models

Rapid development and adjoining of transient finite element models

Contact Info

Product

Resources

About