Postgraduate student of NSU took first place in the All-Russian scientific research competition

A third-year graduate student at the Faculty of Mechanics and Mathematics of NSU Stepan Karmushin took first place in the “Physics and Astronomy” section of the XI All-Russian Competition of Scientific Research Works of Students and Postgraduates. The final stage of the competition took place from September 22 to 25 in Nizhny Novgorod as part of the “Science of the Future — Science of the Youth” forum.

— I learned about the competition from my graduate student friends. This year, I applied for the first time. For the competition, I submitted a work that combines the results of three of our studies on modeling viscoelastic fluids. This format provides an opportunity to showcase the interconnection of the obtained results and receive feedback from researchers outside of one’s own scientific team. The competition allowed presenting them together and discussing them with experts, — Stepan shares.

Stepan presented the work “Modeling of unsteady flows of viscoelastic liquids using nonlinear hyperbolic models.”

— It is dedicated to describing the movement of fluids that simultaneously possess viscosity and elasticity. Such properties are found, for example, in polymer solutions and certain gel compositions used in technological processes. These fluids have a kind of “memory”: their response depends on how they were deformed previously.

If the flow regime changes abruptly, the stresses inside the fluid will rearrange over some time. Moreover, the flow can become heterogeneous: adjacent layers arise in which the fluid slides with different intensities. This phenomenon is called shear banding. We investigate how such structures form and how they affect the overall behavior of the fluid. To do this, we build and study mathematical models, perform calculations, and compare them with experimental data. The word “hyperbolic” in the title refers to the type of equations. This is significant for us: such a structure of equations allows the use of advanced methods to describe the propagation of perturbations and sharp transitions between different flow states. — explains Stepan.

The competition took place in two stages. First, participants submitted their scientific papers for independent review. Thirty-six people in each section reached the final, where they presented their research in person. This year, the organizers received about 3,400 applications from 81 regions of Russia from representatives of 537 educational and scientific organizations. The papers were evaluated in ten scientific fields.

For the competition, Stepan presented the results of three studies, combining them into one work. At the final stage, he spoke about the general approach to modeling viscoelastic fluids, the results of analytical and numerical studies, as well as a comparison of the calculations with published experimental data.

— In the defense, I demonstrated the formation of a layered flow structure, the dependence of the established regime on the history, and the liquid’s response to changes in external influence, — Stepan says.

One of the questions from the experts was the possible practical application of the developed models. As an example, Stepan spoke about gel injection during hydraulic fracturing. Understanding the internal flow structure of a viscoelastic fluid and its changes under different injection conditions can be important for modeling such technological operations.

Stepan’s research is conducted at NSU and the M. A. Lavrentiev Institute of Hydrodynamics of the Siberian Branch of the Russian Academy of Sciences under the supervision of Doctor of Physical and Mathematical Sciences, Professor of the Russian Academy of Sciences. Sergey Valeryevich Golovin. The work on the results presented at the competition was carried out jointly with Valery Yuryevich Lyapidevsky and By Vladimir Valeryevich Neverov.

— I associate this victory with our joint scientific work. I thank my scientific advisor Sergey Valeryevich Golovin for his guidance and support. I want to express special gratitude to Valery Yuryevich Lyapidevsky and Vladimir Valeryevich Neverov for their scientific mentorship and collaboration on the research.

The impressions of the forum were very positive. I met many smart and motivated young scientists. We shared our research with each other and discussed the tasks in which we could collaborate. When you communicate with people who are passionate about their work, new questions and ideas arise that you don’t always pay attention to in the usual circle of colleagues. We also discussed support measures for young scientists and how to take advantage of them. It was useful to exchange information and hear how colleagues from other research teams perceive these opportunities. This topic was also given attention in the forum program: there were discussions about supporting science and developing the scientific potential of young researchers,

The obtained results are planned to be further developed. The researchers’ immediate task is to move from one-dimensional to two-dimensional flow models and to account for the weak compressibility of the fluid. In the future, the approach may be applied to modeling the injection of viscoelastic compositions, well kill operations, and reservoir fracturing.

— In simple terms, this means that the model will allow a slight change in the density of the fluid under the influence of pressure. This transition is considered as a way to construct multidimensional models with a hyperbolic structure. Preserving this structure will enable continued use of the methods for analyzing and calculating waves and discontinuities that we apply in one-dimensional problems. Next, it is necessary to investigate the properties of the resulting systems, determine the conditions for their hyperbolicity, develop numerical algorithms, and validate the computations against experimental data. The applied perspective is seen in modeling the injection of viscoelastic compositions, well killing, and hydraulic fracturing. It is important here to establish in which regimes a detailed consideration of the internal structure of the fluid truly improves predictions and where simpler models no longer provide sufficient accuracy. — explains the graduate student.

For Stepan, participating in the competition became an opportunity to receive external evaluation of his scientific work and to meet other young researchers.

— When you work on one topic for a long time, the evaluation of specialists who look at it from the outside is especially useful. Recognition at such a contest gives more confidence that the chosen direction deserves further development. I hope that the acquaintances made at the forum will continue in joint research, — concludes the winner.

Congratulations to Stepan and we wish him further success in his research activities!