Investigation of Marangoni convection with high-fidelity simulations for metal melt pool dynamics

2019 ◽  
Author(s):  
R Barney
Keyword(s):  
Marangoni Convection ◽  
High Fidelity ◽  
Metal Melt ◽  
Melt Pool ◽  
High Fidelity Simulations

scholarly journals Peering inside a cough or sneeze to explain enhanced airborne transmission under dry weather

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kai Liu ◽  
Majid Allahyari ◽  
Jorge S. Salinas ◽  
Nadim Zgheib ◽  
S. Balachandar
Keyword(s):  
High Fidelity ◽  
Substantial Variation ◽  
Ambient Conditions ◽  
Airborne Transmission ◽  
Social Distancing ◽  
Virtual Experiments ◽  
Long Time ◽  
Simulation Results ◽  
High Fidelity Simulations ◽  
Droplet Nuclei

AbstractHigh-fidelity simulations of coughs and sneezes that serve as virtual experiments are presented, and they offer an unprecedented opportunity to peer into the chaotic evolution of the resulting airborne droplet clouds. While larger droplets quickly fall-out of the cloud, smaller droplets evaporate rapidly. The non-volatiles remain airborne as droplet nuclei for a long time to be transported over long distances. The substantial variation observed between the different realizations has important social distancing implications, since probabilistic outlier-events do occur and may need to be taken into account when assessing the risk of contagion. Contrary to common expectations, we observe dry ambient conditions to increase by more than four times the number of airborne potentially virus-laden nuclei, as a result of reduced droplet fall-out through rapid evaporation. The simulation results are used to validate and calibrate a comprehensive multiphase theory, which is then used to predict the spread of airborne nuclei under a wide variety of ambient conditions.

High-fidelity simulations of moving and flexible airfoils at low Reynolds numbers

2009 ◽  
Vol 46 (5) ◽  
pp. 903-922 ◽  
Author(s):  
Miguel R. Visbal ◽  
Raymond E. Gordnier ◽  
Marshall C. Galbraith
Keyword(s):  
Reynolds Numbers ◽  
High Fidelity ◽  
Low Reynolds Numbers ◽  
Low Reynolds ◽  
High Fidelity Simulations ◽  
Flexible Airfoils

A formulation for high-fidelity simulations of pool boiling in low gravity

2019 ◽  
Vol 120 ◽  
pp. 103099 ◽  
Author(s):  
Akash Dhruv ◽  
Elias Balaras ◽  
Amir Riaz ◽  
Jungho Kim
Keyword(s):  
Pool Boiling ◽  
High Fidelity ◽  
Low Gravity ◽  
High Fidelity Simulations

LPC Blade and Non-Axisymmetric Hub Profiling Optimization Using Multi-Fidelity Non-Intrusive POD Surrogates

2017 ◽  
Author(s):  
Tariq Benamara ◽  
Piotr Breitkopf ◽  
Ingrid Lepot ◽  
Caroline Sainvitu
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
High Fidelity ◽  
Present Contribution ◽  
Compressor Blades ◽  
High Fidelity Simulations ◽  
Optimization Methodology ◽  
Set Up ◽  
Automated Optimization ◽  
Proper Orthogonal

The present contribution proposes a Reduced Order Model based multi-fidelity optimization methodology for the design of highly loaded blades in low pressure compressors. Environmental, as well as, economical limitations applied to engine manufacturers make the design of modern turbofans an extremely complex task. A smart compromise has to be found to guarantee both a high efficiency and a high average stage loading imposed for mass reduction constraints, while satisfying stability requirements. The design of compressor blades, usually involves at the same time a dedicated parametrization set-up in highdimensional space and high-fidelity simulations capturing, at least, efficiency and stability as most impacting phenomena. Despite recent advances in the high-performance computing area, introducing high-fidelity simulations into automated optimization, or even surrogate assisted optimization, loops still stands as a endeavor for engineers. In this framework, the proposed methodology is based on multi-fidelity surrogate models capable of representing the physics at hand in reduced spaces inferred from both precise, albeit costly, high-fidelity simulations and abundant, yet less accurate lower-fidelity data. Finally, we investigate the coupling of the proposed hierarchised multi-fidelity non-intrusive Proper Orthogonal Decomposition based surrogates with an evolutionary algorithm to reduce the number of high-fidelity simulation calls towards the targeted optimum.

High-fidelity simulations and field measurements for characterizing wind fields in a utility-scale wind farm

2021 ◽  
Vol 281 ◽  
pp. 116115
Author(s):  
Xiaolei Yang ◽  
Christopher Milliren ◽  
Matt Kistner ◽  
Christopher Hogg ◽  
Jeff Marr ◽  
...  
Keyword(s):  
Wind Farm ◽  
Field Measurements ◽  
High Fidelity ◽  
Wind Fields ◽  
High Fidelity Simulations ◽  
Utility Scale
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