Towards Adaptive Grids for Atmospheric Boundary-Layer Simulations

• Published in: Boundary-layer meteorology 2018-06, Vol.167 (3), p.421-443
• Main Authors: van Hooft, J. Antoon, Popinet, Stéphane, van Heerwaarden, Chiel C., van der Linden, Steven J. A., de Roode, Stephan R., van de Wiel, Bas J. H.
• Format: Article
• Language: English
• Subjects: Adaptive algorithms; Adaptive mesh refinement; Analysis; Atmospheric boundary layer; Atmospheric flows; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Boundary layers; Computational fluid dynamics; Computer simulation; Direct numerical simulation; Direct numerical simulations; Diurnal cycle; Diurnal variations; Domain names; Dynamic meteorology; Earth and Environmental Science; Earth Sciences; Finite element method; Fluid mechanics; Grid refinement (mathematics); Large eddy simulation; Large eddy simulations; Mathematical models; Mechanics; Meteorology; Mixed layer; Numerical analysis; Numerical simulations; Ocean, Atmosphere; Oceanic eddies; Physics; Research Article; Sciences of the Universe; Simulation; Turbulence; Turbulence (Fluid dynamics); Velocity; Vortices
• ISSN: 0006-8314; 1573-1472
• DOI: 10.1007/s10546-018-0335-9

We present a proof-of-concept for the adaptive mesh refinement method applied to atmospheric boundary-layer simulations. Such a method may form an attractive alternative to static grids for studies on atmospheric flows that have a high degree of scale separation in space and/or time. Examples include the diurnal cycle and a convective boundary layer capped by a strong inversion. For such cases, large-eddy simulations using regular grids often have to rely on a subgrid-scale closure for the most challenging regions in the spatial and/or temporal domain. Here we analyze a flow configuration that describes the growth and subsequent decay of a convective boundary layer using direct numerical simulation (DNS). We validate the obtained results and benchmark the performance of the adaptive solver against two runs using fixed regular grids. It appears that the adaptive-mesh algorithm is able to coarsen and refine the grid dynamically whilst maintaining an accurate solution. In particular, during the initial growth of the convective boundary layer a high resolution is required compared to the subsequent stage of decaying turbulence. More specifically, the number of grid cells varies by two orders of magnitude over the course of the simulation. For this specific DNS case, the adaptive solver was not yet more efficient than the more traditional solver that is dedicated to these types of flows. However, the overall analysis shows that the method has a clear potential for numerical investigations of the most challenging atmospheric cases.