NWM-LES for turbulent boundary layers


SNIC 2016/1-440


SNAC Medium

Principal Investigator:

Mattias Liefvendahl


Uppsala universitet

Start Date:


End Date:


Primary Classification:

20301: Teknisk mekanik

Secondary Classification:

20306: Strömningsmekanik och akustik

Tertiary Classification:

10105: Beräkningsmatematik





This investigation forms part of a VR-funded research project (led by me) concerned with near-wall models for LES (NWM-LES). The research project was started during the spring 2013 and is planned to end in the fall 2018, with the PhD defence of the two students recruited for the project. This investigation concerns the simulation of canonical flow problems dominated by turbulent boundary layers, and their separation. This project builds on two previous Medium Allocations (SNIC 2013/1-241 & SNIC 2014/1-281) at Uppmax, and one previous (SNIC 2015/1-310) at PDC. During the previous allocations, the performance of the computational environment (tintin/UPPMAX), the software and the overall work-cycle were evaluated for the type of simulations of interest. In addition to this preliminary simulation campaigns on transient flow cases were carried out. A significant development and assessment of turbulent inflow conditions for boundary layers was carried out. The current proposal builds directly on the previous ones. The bulk of the computations will consist of the simulation of turbulent boundary layers with/without separation, using NWR/NWM-LES. A particular challenging case will be in focus (see Bentaleb et al.,J.Turbulence,2014). A typical simulation can use 1000 cores and run for 24hrs, but there will be large differences in the number of cores and the simulation time required. Post-processing has a significant requirement on internal memory and graphics since it involves the manipulation of data in three space dimensions represented on a computational grid with in the order of 5-100 million cells. A suitable workcycle for the hardware at PDC was developed during SNIC 2015/1-310.