In this webinar we invite entrants from the 2023 ARCHER2 Image and Video Competition to talk about their work, and the science behind their stunning images and videos.
This online session is open to all. It will use the Blackboard Collaborate platform.
Dr Guglielmo Vivarelli
Imperial College London, Aeronautical Engineering
High Pressure Jet Engine Turbine Blade Transitional Flow
The image shows an implicit Large Eddy simulation of the LS89 high-pressure turbine blade, a component typically found at the exit of a jet engine combustor. The flow field accelerates rapidly over a very short distance. For these particular conditions, flow transitions to 3D around the leading edge of the blade as shown by the wall shear stresses. Gradual increase in strength of the flow instability causes the flow to transition to turbulence with vortices appearing at the trailing edge. The back plane displays the time averaged variation of Mach number ranging from a value of approximately 0.15 at the inlet to nearly 1 in the latter stages of the blade. The solution uses a second order polynomial expansion and was simulated on Archer2 deploying 100 nodes at a time. This work has been carried out in collaboration with Rolls-Royce plc.
Dr Max Holloway and Dr Dmitry Aleynik
Scottish Associaition for Marine Science
Fine-scale numerical system for prediction nearshore upwelling in Canaria Basin and carbon removal, 3D animation of temperature distribution
The coupled atmosphere-ocean circulation model of the Canary Current Upwelling System predicts the timing and position of filaments and stripes of colder seawater enriched with higher levels of dissolved nutrients over five days. The intake seawater pipes are feeding a prototype novel sustainable protein farm located in a desert area near the coast. An unstructured Finite-Volume Coastal Ocean Model with unprecedented resolution (100m) allows assessment of the dispersion of de-acidified water discharged from shallow basins, where dissolved carbon dioxide is naturally consumed by growing microalgae. The ponds are the size of a football pitch, expected to scale up to 1000ha. Physical oceanographic measurements over different seasons helped to calibrate and then evaluate the accuracy of model predictions. Development of the weather (WRF) and ocean (FVCOM) components of the regional hydrodynamic modelling system, test runs on ARCHER2 HPC and visualization (cooperation with M.Holloway) were supported by Innovate-UK (Agri-SATT grant) and NERC.
Juan Carlos Bilbao-Ludena
Imperial College London
The self-amplification and the structured chaotic sea
The picture shows the instantaneous generation of strain (light blue) by the mechanism of self-amplification of strain (purple contour) in a turbulent flow generated by a wing. A nonlinear process distinctive to turbulence. The contour slices show the values of the alignments of the vorticity vector and the intermediate eigenvector of the strain. This alignment plays a crucial role in the magnitude of vortex stretching, a process that regulates and contributes to the generation of strain. The present simulation was obtained with the parallel code Pantarhei on Archer2 which enabled us to have access to novel geometrical features of turbulence which can help us understand better their complex structure. Particularly, in flows of industrial relevance far from isotropic/homogeneous assumptions which would help us elucidate the origins of the small-scale dynamics.
Dr Oleksandr Zhdanov
University of Glasgow, James Watt School of Engineering
Flow past a succulent-inspired cylinder
Unlike humans and animals, plants are sessile and cannot seek shelter from wind. Most plants rely on reconfiguration to reduce the wind loadings they experience. However, this strategy is not possible for tall arborescent cacti and succulents since they have an inflexible structure. Nevertheless, they can withstand high wind loadings without being uprooted. In this project, passive flow control used by succulents was investigated using large eddy simulations performed on ARCHER2. The studied four-ribbed cylinder is inspired by several succulents of the Euphorbiaceae family. Its aerodynamic properties were investigated for different orientations relative to the wind direction The image shows complex vortical structures around and in the wake of the cylinder. Reattachment of the flow separated from the upstream rib at the downstream rib can be observed over the bottom part of the succulent, leading to reduction of the drag force experienced by the succulent at this orientation.
Dr Jian Fang
Scientific Computing Department, STFC Daresbury Laboratory
Dance with Fire
This video illustrates the interaction between turbulence and a hydrogen flame. Turbulence fluctuations disrupt the combustion, by stretching and bending the flame surface and altering the chemical reaction inside the reaction zone. In the meantime, the high temperature of the combustion products caused by the heat released from the flame dampens the turbulence, resulting in quiet fluids downstream. This dynamic interaction resembles a dance between turbulence and flame. The blue-white worm-like structures represent vortical motion from turbulence, and the flame is visualised with the iso-surface of temperature (400K-1200K), rendered with heat release rate. The result is obtained by the direct-numerical simulation with the high-order finite-difference method provided by the open-source ASTR code.