English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The predictive accuracy of wall-modelled LES is influenced by a combinationof the subgrid model, the wall model, the numerical dissipation inducedprimarily by the convective numerical scheme, and also by the density andtopology of the computational grid. The latter factor is of particularimportance for industrial flow problems, where unstructured grids are typicallyemployed due to the necessity to handle complex geometries. Here, a systematicsimulation-based study is presented, investigating the effect of grid-cell typeon the predictive accuracy of wall-modelled LES in the framework of ageneral-purpose finite-volume solver. Following standard practice for meshingnear-wall regions, it is proposed to use prismatic cells. Three candidateshapes for the base of the prisms are considered: a triangle, a quadrilateral,and an arbitrary polygon. The cell-centre distance is proposed as a metric todetermine the spatial resolution of grids with different cell types. Thesimulation campaign covers two test cases with attached boundary layers:fully-developed turbulent channel flow, and a zero-pressure-gradient flat-plateturbulent boundary layer. A grid construction strategy is employed, whichadapts the grid metric to the outer length scale of the boundary layer. Theresults are compared with DNS data concerning mean wall shear stress andprofiles of flow statistics. The principle outcome is that unstructuredsimulations may provide the same accuracy as simulations on structuredorthogonal hexahedral grids. The choice of base shape of the near-wall cellshas a significant impact on the computational cost, but in terms of accuracyappears to be a factor of secondary importance.

Predictive Accuracy of Wall-Modelled Large-Eddy Simulation on Unstructured Grids