1. Modelling proton tunnelling in DNA replication
* * * Winning Image and overall competition winning entry * * *
Max Winokan, University of Surrey, Quantum Biology DTC
Proton transfer between the DNA bases can lead to mutagenic Adenine-Thymine tautomers. In our work, we determine that the energy required for generating tautomers radically changes during the separation of double-stranded DNA. Our results demonstrate that the unwinding of DNA by a helicase enzyme could significantly enhance the stability of tautomeric base pairs and provide a feasible pathway for DNA spontaneous mutations. This image shows the site of such a double proton transfer in a A-T base pair within the nucleic acid duplex. To produce the image atomic coordinates were taken from molecular dynamics simulations (Gromacs on Archer2) before being rendered in VMD. A Van der Waals envelope was added to show the atoms used in quantum chemical models. The image has been further altered in Photoshop to highlight the delocalised nature of the tunnelling proton. The quantum chemical calculations were performed with NWChem on Archer2.
2. Large Eddy Simulation of Cross-Ventilation of Buildings using uDALES 2.0 Codebase
Dr Dipanjan Majumdar, Imperial College London, Civil and Environmental Engineering Department
uDALES is an open-source large-eddy simulation framework designed to simulate unsteady flows in the built environment. It encompasses airflow, sensible and latent heat transfer, and pollutant dispersion within the urban atmospheric boundary layer. The framework employs the immersed boundary method to resolve buildings and incorporates wall functions for surface shear stresses and heat fluxes. A three-dimensional surface energy balance model enables a two-way coupling for man-made and vegetative materials. To optimize performance, uDALES uses two-dimensional domain decomposition for parallelization on supercomputers like ARCHER2, allowing exascale computing. The presented video was generated while testing viability of the latest version uDALES 2.0 in handling indoor-outdoor flow interactions. In this regard, we simulated the cross-ventilation in a generic isolated enclosure, based on the work of Hooff et al. (2017). The video reveals the instantaneous stream-wise velocity as the flow exits through the downstream window.
3. Unsteady Flow Over Random Urban-like Obstacles: A Large Eddy Simulation using uDALES 2.0 Codebase
Dr Dipanjan Majumdar, Imperial College London, Civil and Environmental Engineering Department
uDALES stands as an open-source large-eddy simulation framework, specifically designed to tackle unsteady flows within the built environment. It is capable of simulating airflow, sensible and latent heat transfer, and pollutant dispersion within the urban atmospheric boundary layer. The simulation framework adopts the immersed boundary method to resolve buildings, supplemented with wall functions to account for surface shear stresses and heat fluxes. Additionally, a three-dimensional surface energy balance model establishes a two-way coupling, accommodating both man-made and vegetative materials. To achieve optimal performance, uDALES utilizes two dimensional domain decomposition, facilitating parallelization and resource utilization on supercomputers like ARCHER2 for exascale computing. The presented figure was generated while validating the latest version uDALES 2.0 against a classical study by Xie et al. (2008) on flow over random urban-like obstacles. It showcases the instantaneous stream-wise velocity contour at a spanwise plane intersecting the tallest building within the simulated domain.
4. Revealing Real-time Attosecond Dynamics in Xenon
Lynda Hutcheson, Queen's University Belfast
Advances in laser and computer technology allow us to investigate dynamics on the attosecond (10^(-18) s) timescale: the natural timescale of electronic motion. Using ARCHER2, we perform state-of-the-art simulations with the R-matrix with time-dependence (RMT) codes, treating interactions between multi-electron atoms/molecules and arbitrary laser fields.
The video shows how the absorption of laser light varies as a function of time and energy during ionisation of a xenon atom. Effectively, the three peaks represent the presence of ‘holes’ left by ionisation. The peaks build up as the laser ionises the xenon, but oscillate at twice the frequency of the driving field. These oscillations, through careful analysis, reveal an alternative ionisation pathway interfering with direct ionisation. These real-time studies of attosecond dynamics are only possible using massively parallel calculations on ARCHER2.
5. Revealing Real-time Attosecond Dynamics in Xenon
Lynda Hutcheson, Queen's University Belfast
Advances in laser and computer technology allow us to investigate dynamics on the attosecond (10^(-18) s) timescale: the natural timescale of electronic motion. Using ARCHER2, we perform state-of-the-art simulations with the R-matrix with time-dependence (RMT) codes, treating interactions between multi-electron atoms/molecules and arbitrary laser fields.
The image shows how the absorption of laser light varies as a function of time and energy during ionisation of a xenon atom. Effectively, the three peaks represent the presence of ‘holes’ left by ionisation. The peaks build up as the laser ionises the xenon, but oscillate at twice the frequency of the driving field. These oscillations, through careful analysis, reveal an alternative ionisation pathway interfering with direct ionisation. These real-time studies of attosecond dynamics are only possible using massively parallel calculations on ARCHER2
6. Late-time drop breakup interacting with uniform surrounding airflows
Kaitao Tang, Department of Engineering Science, University of Oxford
We conduct high-resolution direct numerical simulations investigating the deformation and breakup of liquid drops interacting with uniform ambient airflows. The morphology of the drop before its breakup is governed by a competition between inertial and capillary forces; and in our regime of interest, the droplet deforms into a thin bag film attached to a toroidal rim. A recently developed numerical algorithm is applied to artificially create holes on the thin bag film and initiate its fragmentation, so that the resulting liquid drop statistics are not dependent on the grid size. The image shows the film breakup process with this algorithm applied, where one can observe the expansion of holes on the film, the formation of liquid ligaments following the merge two hole rims, and the subsequent breakup of the ligaments producing droplets with different sizes, which often experience shape oscillations.
7. Oil into a ketton carbonate rock saturated with water
Dr Liang Yang, Cranfield University, Energy and Sustainability
This simulated a pure injection drainage process with a non-wetting phase using the Open-source Taichi-LBM3D code for the Ketton carbonate, supported by the eCSE Archer2 grant: 'MPI implementation of open-source fully-differentiable multiphase lattice Boltzmann code'. The simulation domain measures 250^3. Excluding the inlet layer, which was initially saturated with oil, the sample was completely saturated with water (the wetting phase). Despite the high capillary pressure, some small pores and throats were not filled with the non-wetting phase. The simulation was performed using Archer2 computational resources and post-processed with Paraview.
08. Growth of hair around a Black Hole
Llibert Aresté Saló, Centre for Geometry, Analysis and Gravitation, School of Mathematical Sciences, Queen Mary University of London
Time evolution of the scalar field (hair) that grows around the remnant Black Hole formed after the merger of two Black Holes in a given modified theory of gravity. This class of theories are of particular interest since they violate the no-hair theorem that applies in General Relativity.
09. Mirroring a Pyroclastic Flow Experiment using Large-Eddy Simulation
* * * Winning Video * * *
Dr Eric Breard, School of Geoscience, University of Edinburgh
The image and video are derived from a Large-Eddy Simulation of a pyroclastic flow, consisting of a hot mixture of air and particles that travel down an inclined channel before spreading across a flat terrain. The simulation mirrors one large-scale experiment conducted in New Zealand and is part of an international initiative to validate numerical models in Volcanology. Turbulent eddies, sedimentation, and vertical density stratification are depicted using the flow's free surface (split in half along the centerline), a vertical slice showing solid concentration, and a solid boundary rendered as glass. The domain encompasses 60 million cells, covering a volume of 28*6*5 m3. The multiphase flow simulation addresses the mass, momentum, and energy equations for all six phases (air plus 5 solid phases) and captures the granular to dilute turbulent regimes. The simulation was run using the US DOE's MFIX solver, utilizing 1200 CPU cores on ARCHER2 for 15 days.
10. Fully general evolution of a field in anti-de Sitter spacetime
Dr Lorenzo Rossi, Queen Mary University of London, School of Mathematical Sciences
The video shows the gravitational evolution of a field in a type of spacetime called anti-de Sitter (AdS). It is obtained from the first and only code able to simulate gravity in AdS in full generality, i.e., with dynamics along all 3 spatial dimensions. The simulation is performed on Archer2 on a 3-dimensional Cartesian grid and the video displays the x=0 slice. The boundary of AdS is a sphere, whose x=0 slice is the edge of the disk displayed in the video.
AdS is crucial for the celebrated AdS/CFT duality, a precise correspondence between gravity in AdS (such as the one displayed in the video) and the physics of a conformal field theory (CFT) at the AdS boundary. In turn, CFTs provide insights on theories of quantum particles (there are no other tools to study such theories in the strong coupling regime).
11. Fully general evolution of a field outside of a rotating black hole in anti-de Sitter spacetime
Dr Lorenzo Rossi, Queen Mary University of London, School of Mathematical Sciences
The video shows the gravitational evolution of a field outside of a rotating black hole immersed in a type of spacetime called anti-de Sitter (AdS). It is obtained from the first and only code able to simulate gravity in AdS in full generality, i.e., with dynamics along all 3 spatial dimensions. The simulation is performed on Archer2 on a 3-dimensional Cartesian grid and the video displays the x=0 slice. The boundary of AdS is a sphere, whose x=0 slice is the edge of the disk displayed in the video.
AdS is crucial for the celebrated AdS/CFT duality, a precise correspondence between gravity in AdS (such as the one displayed in the video) and the physics of a conformal field theory (CFT) at the AdS boundary. In turn, CFTs provide insights on theories of quantum particles (there are no other tools to study such theories in the strong coupling regime).
12. Fully general evolution of a field outside of a rotating black hole in anti-de Sitter spacetime
Dr Lorenzo Rossi, Queen Mary University of London, School of Mathematical Sciences
The image shows four snapshots of the gravitational evolution of a field outside of a rotating black hole immersed in a spacetime called anti-de Sitter (AdS). It is obtained from the first and only code able to simulate gravity in AdS in full generality, i.e., with dynamics along all 3 spatial dimensions. The simulation is performed on Archer2 on a 3-dimensional Cartesian grid and the snapshots display the x=0 slice. The boundary of AdS is a sphere, whose x=0 slice is the edge of the disk displayed in the snapshots.
AdS is crucial for the celebrated AdS/CFT duality, a precise correspondence between gravity in AdS (such as the one displayed in the image) and the physics of a conformal field theory (CFT) at the AdS boundary. In turn, CFTs provide insights on theories of quantum particles (there are no other tools to study such theories in the strong coupling regime).
13. Fully general evolution of a CFT field dual to gravity outside of a rotating black hole in anti-de Sitter spacetime
Dr Lorenzo Rossi, Queen Mary University of London, School of Mathematical Sciences
According to the celebrated AdS/CFT, gravitational physics in a certain spacetime called anti-de Sitter (AdS) is dual to the physics of a conformal field theory (CFT) at the AdS boundary. In turn, CFTs provide insights on theories of quantum particles (there are no other tools to study such theories in the strong coupling regime). The boundary of AdS is the sphere displayed in the video.
The video shows the evolution of a CFT field dual to the gravitational evolution of a field outside of a rotating black hole immersed in AdS. It is obtained from the first and only code able to simulate gravity in AdS in full generality, i.e., with dynamics along all 3 spatial dimensions. The simulation is performed on Archer 2 on a 3-dimensional Cartesian grid. Subsequently, the field values on this grid are used to extrapolate the displayed values on the sphere.
14. Fully general evolution of the CFT energy density dual to gravity outside of a rotating black hole in anti-de Sitter spacetime
Dr Lorenzo Rossi, Queen Mary University of London, School of Mathematical Sciences
According to the celebrated AdS/CFT, gravity in the so-called anti-de Sitter (AdS) spacetime is dual to the physics of a conformal field theory (CFT) at the AdS boundary. In turn, CFTs provide insights on theories of quantum particles (there are no other tools to study such theories in the strong coupling regime). The boundary of AdS is the sphere displayed in the video.
The video shows the evolution of the CFT energy density dual to the gravitational evolution of a field outside of a rotating black hole immersed in AdS. It is obtained from the first and only code able to simulate gravity in AdS in full generality, i.e., with dynamics along all 3 spatial dimensions. The simulation is performed on Archer2 on a 3-dimensional Cartesian grid. Subsequently, the values of the corresponding function on this grid are used to extrapolate the displayed values on the sphere.
15. Dance with Fire
Dr Jian Fang, Scientific Computing Department, STFC Daresbury Laboratory
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.
16. Fine-scale numerical system for prediction nearshore upwelling in Canaria Basin and carbon removal, 3D animation of temperature distribution
Dr Dmitry Aleynik and Dr Max Holloway, SAMS
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.
17. Flow past a succulent-inspired cylinder
Dr Oleksandr Zhdanov, University of Glasgow, James Watt School of Engineering
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.
18. Secondary currents in turbulent channel flow over streamwise ridges
Dr Oleksandr Zhdanov, University of Glasgow, James Watt School of Engineering
The image shows two pairs of time-averaged secondary current vortices formed over streamwise-aligned triangular ridges placed on a smooth wall. These results were obtained from direct numerical simulations of turbulent channel flow performed on the UK National Supercomputing Service ARCHER2. The secondary currents are visualised with isosurfaces of swirl strength coloured by streamwise vorticity. Although the ridge height is only 8% of the channel half-height, the spacing between ridges is of the order of the channel half-height resulting in pronounced secondary currents that occupy a significant part of the channel. Due to their large extent, they affect the entire flow invalidating Townsend’s hypothesis for the outer-layer similarity of rough-wall turbulence. Understanding the role of secondary currents in momentum and energy transfer will lead to more accurate models for drag prediction and facilitate development of a framework for the identification, prediction, and control of secondary currents in engineering and environmental applications.
19. Silico model for assessing individual responses to irregular heart rhythm treatments.
* * * Winning Early Career entry * * *
Carlos Edgar Lopez Barrera, Queen Mary University of London, SEMS
This video demonstrates the creation of a personalized in silico model for assessing individual responses to irregular heart rhythm treatments. These customized computational models can predict how a patient will react to therapy and facilitate virtual trials. The process starts with a point cloud extracted from a segmented MRI scan, providing a spatial representation of the atrium. These points are interconnected to form a 3D finite element mesh that reflects the patient's unique anatomy. The cardiac tissue's directional properties, influenced by atrial fiber orientation, are incorporated from a DT-MRI atlas. The model then simulates electrical activity and electrograms using the openCARP solver to explore irregular heart rhythms like atrial fibrillation. Post-simulation analysis identifies critical atrial fibrillation regions. Procedures like radiofrequency catheter ablation or anti-arrhythmic drug administration can be virtually tested to predict the patient's individualized response, as demonstrated in this case with pulmonary vein isolation ablation therapy.
20. Exploring the Impact of Electrogram Data Analysis at Different Spatial Resolutions in Models of Atrial Fibrillation.
Carlos Edgar Lopez Barrera, Queen Mary University of London, SEMS
This image illustrates a study on clinical measurement locations' impact on understanding and treating diseases, including irregular heart rhythms such as atrial fibrillation (AF). The spatial resolution of AF electrogram data is crucial for interpreting the underlying AF mechanism and successfully treating AF. We investigated this through simulating AF electrogram recordings at different spatial resolutions
21. The Galewsky Jet with a moving mesh
Dr Jack Betteridge, Imperial College London, Mathematics
This video shows a simulation of a jet stream around the North Pole over the period of one week. The rotating shallow-water equations are solved on the surface of a sphere, using the same numerical methods that are used in the Met Office’s next-generation weather forecasting model. In this animation, the mesh moves, with the resolution adapting to the gradient of the vorticity field. This allows the computational resources to be concentrated to the most complex features of the fluid. The shaded region shows the vorticity of the fluid, while the arrows show the size and direction of the wind. The contours show the streamlines along which the fluid flows.
Surface of the Earth photograph image credit: NASA - Visible Earth Blue Marble: Land Surface, Shallow Water, and Shaded Topography. Copyright information from https://visibleearth.nasa.gov/image-use-policy
22. Aerofoil Turbulence Generation using Vortex Generators
Clinton Naicker, Brunel University London - Department of Mechanical and Aerospace Engineering
The picture shows Q-criterion iso-surfaces coloured by mean velocity magnitude, demonstrating the natural transition to turbulent flow for the clean aerofoil (left) and the forced transition to turbulent flow (right). Wind tunnel experiments are limited by the inflow velocity and size of the test section. Therefore, to test the effectiveness of noise reduction mechanisms, lower speed experiments use "tripping" to force the transition of laminar flow to turbulent flow. To make a like-for-like comparison with the experiments run at the Brunel Aeroacoustics Lab, CFD analysis was carried out at a Reynolds number of 200,000 on an aerofoil section making use of a "zigzag" type trip. The Large-Eddy Simulation was conducted using OpenFOAM v2212 on ARCHER2. Postprocessing was carried out in ParaView.
23. Gravity current propagating past a cylinder
Peter Brearley, Imperial College London, Department of Aeronautics
Gravity currents are fluid flows driven by density differences, causing the denser fluid to propagate across a surface through the less dense fluid. They are the means of a range of oceanic, atmospheric and geological flows that shape and regulate the environment that we live in. Oceanic gravity currents include the vast deep sea currents caused by differences in temperature or salinity. In the atmosphere, gravity currents occur as cold fronts, where cold, dense air displaces warm, light air. When interacting with physical objects such as geological formations, submarine structures or city landscapes, gravity currents can exhibit complex behaviours. A two-way interaction occurs where the object disrupts the flow while the flow is exerts considerable force on the object. This mutual interaction is of particular importance when considering the durability of offshore structures, pipelines and buildings.
24. Bulk simulated Phosphate-based bioglass by developed ReaxFF potential
Dr Zohreh Fallah, Department of Materials, Loughborough University
Phosphate-based glasses (PBGs) have different applications based on their dissolution properties which can be tuned over several orders of magnitude via their composition targeting the desired application. The ReaxFF forcefield can describe the formation and dissociation of chemical bonds during molecular dynamics simulation. We developed ReaxFF parameters of ternary PBGs which include the interaction between phosphorus and calcium atoms, as these are the compositions used in biomedical applications. Optimization of the parameters has been done against a large training set of quantum mechanical data, mostly from small boxes of the phosphate glasses using ARCHER2. The developed ReaxFF parameters can describe structural properties of both binary and ternary glass compositions which are consistent with the experimental results.
25. Development of ReaxFF potential to investigate dissolution behaviour of phosphate-based bioglasses
Dr Zohreh Fallah, Department of Materials, Loughborough University
Phosphate-based bioglasses (PBGs) have different biomedical applications in hard and soft tissue engineering due to their dissolution properties. The ReaxFF forcefield can describe the formation and dissociation of chemical bonds allowing us to understand the dissolution mechanisms of the glass at atomic level. The parameterization of the ReaxFF parameters of the glasses has been done on the training set of quantum mechanical data including interatomic forces, charge calculation, and different differential energy calculations mostly on small boxes of glasses by GARFfield framework using ARCHER2. We developed ReaxFF parameters of ternary PBGs which include the interaction between phosphorus and calcium atoms. The developed ReaxFF parameters can describe well enough the structural properties of both binary and ternary phosphate-based glasses, consistent with the experimental results. Therefore, with new reparameterization of ReaxFF parameters on training data including the interaction of water molecules with PBGs, we could directly investigate the dissolution behaviors of PBGs.
26. Pesticide Spray in Drone Downwash
Peter Brearley, Imperial College London, Department of Aeronautics
The video shows a simulation of an agricultural drone dispersing pesticides. Agricultural drones have become invaluable in modern farming for tasks such as monitoring crop health, planting seeds, and spraying fertilisers and pesticides. Drones are especially advantageous for farming uneven terrain that is otherwise difficult for ground-based machinery to navigate. The turbulent air flow from the rotors disperses the fluid more evenly across the land. Understanding and optimising the complex interaction between rotor downwash and pesticide dispersion has the potential to bring significant efficiency improvements to farming, and in doing so contributes towards meeting the global challenge of food security.
27. Progressive zoom into a cross-section of a three-dimensional simulation of Rayleigh-Taylor convection using the Elliptical Parcel-in-Cell method.
Dr Matthias Frey, University of St Andrews
We have developed a three-dimensional model to simulate fluid dynamics using ellipsoidal parcels.
These parcels can deform, split and merge to capture the effects of mixing on the flow.
The parcels carry all the information needed to compute the flow evolution in these simulations.
The simulation shown here starts with a warm fluid below a cold fluid. This unstable stratification leads to the development of a convective, turbulent flow. The cross-section shows that structures in the temperature field develop over a range of scales. The individual ellipses obtained from theintersection of the shown cross-section with the surrounding ellispoidal parcels are visualised.
28. Animation of a three-dimensional simulation of Rayleigh-Taylor convection using the Elliptical Parcel-in-Cell method.
Dr Matthias Frey, University of St Andrews
We have developed a three-dimensional model to simulate fluid dynamics using ellipsoidal parcels.These parcels can deform, split and merge to capture the effects of mixing on the flow.
The simulation shown here starts with a warm fluid below a cold fluid. This unstable stratification leads to the development of a convective, turbulent flow. The animation shows the buoyancy field and the vertical component of vorticity. The line plots show the conversion of potential energy to kinetic energy (left) and the enstrophy (right, this gives a measure of dissipation of kinetic energy).
29. High Pressure Jet Engine Turbine Blade Transitional Flow
Dr Guglielmo Vivarelli, Imperial College London, Aeronautical Engineering
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.
30. High Pressure Jet Engine Turbine Blade in Shocked Flow
Dr Guglielmo Vivarelli, Imperial College London, Aeronautical Engineering
The video shows the Mach number of 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 very high level of suction at the outflow causes a very strong acceleration causing a shock to appear (the flow accelerates from ~60m/s to 280m/s in ~10cm). This interacts with the adjacent blade's wake and the waves emanating off the blade trailing edge are clearly visible. The most complicated aspect in setting up this case is represented by the unsteady boundary layer/shock interaction and the high energy vortices. This particular simulation is 4th order accurate and was run with Nektar++ on Archer2 using a high-order quadrilateral mesh. This work has been carried out in collaboration with Rolls-Royce plc.
31. NACA0012 Turbulent Flow at 12 Degrees Angle of Attack
Dr Guglielmo Vivarelli & Dr Moshen Lahooti, Imperial College London, Aeronautical Engineering & Newcastle University
The image shows the flow transitioning to turbulent right at the beginning of the NACA0012 aerofoil at 12 degrees angle of attack and a Reynolds number of 150000. The flow produces a very large separation region on the upper surface of the wing. This particular simulation was run using the Nektar++ incompressible flow solver on Archer2 nodes due to the very high resolution (polynomial order 11) required to be able to capture the small scales forming at the leading edge. During testing, it was seen that, incorrect physical behaviour would generally be achieved unless a very large amount of resources was not deployed. The overall aim of this study was to understand aerofoil post-stall behaviour. This is critical for micro-air vehicles and wind turbine blades
32. Floating wind platform in wave
Dr Liang Yang and Dr Junxian Wang, Cranfield University, Energy and Sustainability
Floating Offshore Wind Turbines (FOWT) play an important role in offshore renewable energy utilization, contributing to the net-zero target. This simulation conducts a preliminary study on the floating foundation of FOWT in regular waves using an open-source CFD tool (OpenFOAM-ESI). The built-in wave generation and overset mesh technique are adopted to create regular waves and handle the floater's dynamic response. The mesh near the floater (i.e., inner region), generated using meshing software ChopMesh, perfectly fits the structure's surface with excellent quality. Edges of the inner region match the structure's outline, ensuring a smooth transition.
33. The shining stars of turbulence
Juan Carlos Bilbao-Ludena, Imperial College London, Deparment of Aeronautics
This image captures the transformation of a two-dimensional-like shear layer, depicting its journey starting from structured order. Initially, the shear layer appears as an elongated singular shape, but as it undergoes in-viscid fragmentation, it breaks down into smaller sizes, where dissipation levels are present leading into what is known as fully developed turbulence. The bright contrasting contours in the image showcases the levels of linkage between different length scales in the flow. The present simulation was obtained with the parallel code Pantarhei on Archer2, which enable us to reveal new flow physics with the accuracy that is needed.