HSE Scientist Optimises Solution of Hydrodynamics Problems
Supercomputers are no longer required to calculate fluid flows in multiscale problems.
Roman Gaydukov, Associate Professor at the MIEM HSE School of Applied Mathematics, has modelled the fluid flow around a rotating disk with small surface irregularities. His solution allows for predicting fluid flow behaviour without the need for powerful supercomputers. The results have been published in Russian Journal of Mathematical Physics.
Hydrodynamics studies the motion of fluids and their interaction with solid surfaces. This branch of physics makes it possible to understand and predict the behaviour of fluids and gases under various conditions. In particular, the principles of hydrodynamics are used in electrochemistry for calculating the reactions of galvanisation, such as silver molecules adhering to a metal surface, and oxidation, such as patina formation on copper.
These processes use a disk electrode, which is a flat metal plate that rotates in a fluid. To accurately calculate electrochemical reactions, it is essential to understand how the fluid moves around the electrode and what conditions that need to be maintained. To achieve this, scientists must account for numerous variables, while even minor irregularities on the disk surface can greatly influence fluid flow, leading to complex and unexpected effects.
Earlier studies focused solely on symmetrical irregularities, but a scientist at HSE University examined a more complex case. Roman Gaydukov calculated how fluid flow would change with the presence of asymmetrical irregularities on the rotating disk surface.
To do this, he used the method of multideck structures of boundary layers, making it possible to decompose the three-dimensional problem into a series of two-dimensional ones. This method helps solve complex hydrodynamic problems at high Reynolds numbers, where direct modelling is impossible. Although this method has been known since the late 1960s, a rigorous mathematical formulation was only recently developed by the author of the paper together with Professor Vladimir Danilov. The mathematical algorithm of the method can be integrated into any symbolic computation software.
Roman Gaydukov
'Under real conditions, perfectly smooth surfaces do not exist. We have demonstrated how small irregularities on the disk surface affect fluid flow by creating vortex zones and altering the structure of the boundary layer,' explains Roman Gaydukov. 'Our method allows modelling a problem within a few hours, whereas it could take days or even weeks on a supercomputer. This not only saves time but also reduces the cost of computational resources. The method works effectively for large but finite Reynolds numbers.'
The Reynolds number is a dimensionless quantity that describes the relationship between inertial and viscous forces in fluid flow. A large Reynolds number signifies the dominance of inertial forces, which often results in turbulent (chaotic) flows, while a small Reynolds number indicates the dominance of viscous forces, leading to laminar (ordered) flows.
The developed approach can be used to accurately model fluid motion during chemical reactions, with potentially wide applications in industry.
In the future, the scientist plans to extend his research to more complex systems involving interactions between different phases, such as liquid droplets in an air stream or aerosols. This will enable a deeper understanding of the processes in multicomponent and multiphase systems and help improve existing models.
According to Gaydukov, 'Together with my graduate student Nikita Burov, we plan to investigate how the shape of fluid droplets changes as they move through an air flow and how the droplets, as irregularities—including their potential freezing—affect the flow.'
See also:
Working while Studying Can Increase Salary and Chances of Success
Research shows that working while studying increases the likelihood of employment after graduation by 19% and boosts salary by 14%. One in two students has worked for at least a month while studying full time. The greatest benefits come from being employed during the final years of study, when students have the opportunity to begin working in their chosen field. These findings come from a team of authors at the HSE Faculty of Economic Sciences.
Beauty in Details: HSE University and AIRI Scientists Develop a Method for High-Quality Image Editing
Researchers from theHSE AI Research Centre, AIRI, and the University of Bremen have developed a new image editing method based on deep learning—StyleFeatureEditor. This tool allows for precise reproduction of even the smallest details in an image while preserving them during the editing process. With its help, users can easily change hair colour or facial expressions without sacrificing image quality. The results of this three-party collaboration were published at the highly-cited computer vision conference CVPR 2024.
HSE Scientists Have Examined Potential Impact of Nuclear Power on Sustainable Development
Researchers at HSE University have developed a set of mathematical models to predict the impact of nuclear power on the Sustainable Development Index. If the share of nuclear power in the global energy mix increases to between 20% and 25%, the global Sustainable Development Index (SDI) is projected to grow by one-third by 2050. In scenarios where the share of nuclear power grows more slowly, the increase in the SDI is found to be lower. The study has been published in Nuclear Energy and Technology.
HSE Scientists Have Developed a New Model of Electric Double Layer
This new model accounts for a wide range of ion-electrode interactions and predicts a device's ability to store electric charge. The model's theoretical predictions align with the experimental results. Data on the behaviour of the electric double layer (EDL) can aid in the development of more efficient supercapacitors for portable electronics and electric vehicles. The study has been published in ChemPhysChem.
Psychologists from HSE University Discovered How Love for Animals Affects Relationships with People
Researchers from HSE University have identified a connection between attachment to pets and attitudes toward nature and other people. The study found that the more joy people derive from interacting with their pets, the more they want to help others. However, love for animals is not always associated with concern for nature. The findings were published in the Social Psychology and Society journal.
HSE Scientists Propose Using Heart Rate Analysis to Diagnose Anxiety and Depression
A group of scientists at HSE University have discovered how anxiety and depression can be diagnosed by analysing heart rate. It turns out that under mental stress, the heart rate of individuals with a predisposition to mental health disorders differs from that of healthy individuals, especially when performing more complex tasks. These changes in cardiovascular parameters can even be detected using a pulse oximeter or a smartwatch. The study findings have been published in Frontiers in Psychiatry.
Researchers at HSE in St Petersburg Develop Superior Machine Learning Model for Determining Text Topics
Topic models are machine learning algorithms designed to analyse large text collections based on their topics. Scientists at HSE Campus in St Petersburg compared five topic models to determine which ones performed better. Two models, including GLDAW developed by the Laboratory for Social and Cognitive Informatics at HSE Campus in St Petersburg, made the lowest number of errors. The paper has been published in PeerJ Computer Science.
Narcissistic and Workaholic Leaders Guide Young Firms to Success
Scientists at HSE University—St. Petersburg studied how the founder's personal characteristics impact a young firm's performance. It turns out that a narcissist and workaholic who also fosters innovation will effectively grow their company. The paper has been published in IEEE Transactions on Engineering Management.
Biologists at HSE University Warn of Potential Errors in MicroRNA Overexpression Method
Researchers at HSE University and the RAS Institute of Bioorganic Chemistry have discovered that a common method of studying genes, which relies on the overexpression of microRNAs, can produce inaccurate results. This method is widely used in the study of various pathologies, in particular cancers. Errors in experiments can lead to incorrect conclusions, affecting the diagnosis and treatment of the disease. The study findings have been published in BBA.
Green Energy Patents Boost Company Profitability
An ESG strategy—Environmental, Social, and Corporate Governance—not only helps preserve the environment but can also generate tangible income. Thus, the use of renewable energy sources (RES) and green technologies in the energy sector enhances return on investment and profitability. In contrast, higher CO2 emissions result in lower financial performance. This has been demonstrated in a collaborative study by the HSE Faculty of Economic Sciences and the European University at St. Petersburg. Their findings have been published in Frontiers in Environmental Science.