Civil and Structural Engineering, Computational Mechanics, Fluid Flow and Transfer Processes, Applied Mathematics
17
Scopus Publications
Scopus Publications
Numerical Study of Subsonic Hot and Near-Sonic Submerged Jets Based on a Two-Fluid Model Zafar Malikov, Farrukh Nazarov, Sardor Khaydarov Journal of Applied and Computational Mechanics, 2025 This paper discusses the hot subsonic and near-sonic axisymmetric submerged stationary jets flowing from a nozzle with a radius of 25.4 mm. The Mach number at the nozzle exit is 0.376 for a subsonic jet, and for a near-sonic jet, it is 0.985. The Reynolds number for both problems was equal to 5600. A two-fluid turbulence model was used to study these problems. The numerical results of this model were obtained for both the full elliptic and simplified parabolic systems of equations. The SIMPLE procedure was applied to the numerical implementation of the complete elliptic system of equations. In the parabolic system of equations, the marching method of integrating equations in the longitudinal direction is used. The results of the two-fluid model are compared with the results of other known RANS turbulence models, which were obtained using the COMSOL Multiphysics® package, as well as with the experimental data from the NASA database.
Calculation of axisymmetric transonic jet with various turbulence models using comsol multiphysics package F. Kh. Nazarov, S. K. Abdukhamidov, S. S. Fayzulloev, Sh. Sh. Akhmadaliev, T. N. Ibodullaev Aip Conference Proceedings, 2025 In this article, a jet with a radius of 25.4 mm was used.The Mach number at the jet exit for a particular case is approximately M=0.985.In this work, the results are obtained by calculating the jet with various turbulence models using the Comsol Multiphysics package.Jets use a periodic (rotated) mesh with appropriate boundary conditions on the periodic sides of the mesh.The Navier-Stokes equations are discretized using the finite element method (FEM).The results obtained were compared with experiments presented in the NASA database.
Numerical study of Taylor - Cuetta turbulent flow Zafar M Malikov, Farrux Kholiyorovich Nazarov, Murodil Erkinjan son Madaliev Computer Research and Modeling, 2024 В настоящей работе исследован турбулентный поток Тейлора – Куэтта с помощью двухмерного моделирования на базе осредненных уравнений Навье – Стокса (RANS) и нового двухжидкостного подхода к турбулентности при числах Рейнольдса в диапазоне от 1000 до 8000. Исследуется течение, обусловленное вращающимся внутренним и неподвижным внешним цилиндрами. Рассмотрен случай соотношения диаметров цилиндров 1:2. Известно, что возникающее круговое течение характеризуется анизотропной турбулентностью и математическое моделирование таких потоков является сложной задачей. Для описания таких потоков используются либо методы прямого моделирования, которые требуют больших вычислительных затрат, либо достаточно трудоемкие методырейно льдсовых напряжений или же линейные RANS-модели со специальными поправками на вращение, которые способны описывать анизотропную турбулентность. В работе для сравнения различных подходов к моделированию турбулентности представленычисленны е результатылинейны х RANS-моделей SARC, SST-RC, метода рейнольдсовых напряжений SSG/LRR-RSM-w2012, прямого моделирования турбулентности DNS, а также новой двухжидкостной модели. Показано, что недавно разработанная двухжидкостная модель адекватно описывает рассматриваемый поток. Помимо этого, двухжидкостная модель проста для численной реализации и имеет хорошую сходимость.
Numerical Calculation of Turbulent Flow in a Two-Dimensional Flat Diffuser Based on the Comsol Multiphysics Software Farrukh Nazarov, Rabim Fayziev, Sardor Khaydarov, Jonibek Fardayev ACM International Conference Proceeding Series, 2023 Modern economic theory, both at the micro and macro levels, and ever-increasing complexity of economic processes have led to the need to create and improve the use of mathematical modeling and quantitative analysis. On the basis of the latter, one of the areas of economic research emerged and was formed - econometrics. Econometric models and methods are now not only powerful tools for obtaining new knowledge in economics, but also a widely used apparatus for making practical decisions in forecasting, banking, and business. The development of information technologies and special ap-plication programs, the improvement of analysis methods have made econ-ometrics a powerful tool for economic research. The paper presents the prob-lem of numerical calculation of turbulent flow in a channel with a minor ob-stacle based on the COMSOL MULTIPHYSICS® software package. The SA and SST models were used for the numerical calculation of turbulent flow in the channel. The results obtained using the COMSOL MULTIPHYSICS® package were compared with experimental data and also analyzed in term of computational load. The results are obtained for Reynolds number Re = 20,000.
Numerical Study of Laminar Flow Using Various Difference Schemes Farrukh Nazarov, Murodil Madaliev, Rabim Fayziev, Bakhtiyor Murodullaev ACM International Conference Proceeding Series, 2023 Mathematical modeling plays a key role in econometrics as it is a field where statistics and mathematics are used to analyze economic data and develop economic models. This paper presents a numerical study of laminar flow in a suddenly expanding channel using various computational schemes. The Na-vier-Stokes equation was used to numerically solve the laminar flow in the channel. To calculate the Navier-Stokes equation, an explicit scheme of the third order of accuracy QUICK (Quadratic Upstream Interpolation for Con-vective Kinematics) and a second order of accuracy implicit against flow US (Up-wind scheme) schemes were used. For the difference approximation of the initial equa-tions, the finite difference method was applied, and the rela-tionship between velocities and pressure was found using the SIMPLE pro-cedure. The paper presents a two-dimensional geometry of an expansion channel with an expansion ratio of 1:2. Based on this geometry, results were obtained with Reynolds numbers of 100, 400, 600, and 800. Velocity plots at Reynolds numbers of 100 and 400 were compared with experimental re-sults at different sections. Graphs of friction coefficients were obtained for various values of Reynolds numbers. Speed profiles were compared using QUICK and implicit schemes. In addition, longitudinal velocity isolines are present-ed for Reynolds numbers of 100, 400, 600, and 800. It is shown that the re-sults are practically the same for the two presented finite-difference schemes for small Reynolds numbers. At large values of the Reynolds number, the numerical results obtained by the implicit scheme showed better agreement with the experimental results than by the QUICK scheme. And also the pa-per presents the primary and secondary flow vortices as isolines.
Development of new efficient technology for extraction of fine dust impurities from cotton M. E. Madaliev, D. P. Navruzov, F. Kh. Nazarov, Y. Y. Hamrayev, S. A. Boltayev, S. K. Abdukhamidov E3s Web of Conferences, 2023 To date, the problem of creating an effective technology for the extraction of fine dust pollution from cotton has not been solved. This article provides a solution to this problem. The socio-economic significance of the study lies in the fact that the proposed device is associated with significant savings in energy costs for cleaning cotton from dust. After the contaminated cotton enters the threshing floor, under great pressure, fine trash settles firmly inside the cotton. It makes it very difficult to process and clean it in cotton factories. Therefore, the cleaning process of cotton has to be repeated several times. The cost of energy consumed during cleaning increases significantly and the cotton fiber quality is reduced. The device proposed in the article cleans the collected cotton from impurities during machine harvesting. The process of cleaning cotton at this stage is very effective. As a result, the cost of harvested cotton is reduced, which increases the income of cotton farmers and workers employed in cotton factories. In addition, it causes an increase in the quality of textile products. Another socio-economic significance of the device proposed in the article is that it can be installed on a cotton harvester and in other places. In addition, it can be used not only to clean cotton but also to clean other substances from fine dust. As a result of practical research, technology has been developed to extract small contaminants from cotton.
Comparison of advanced turbulence models for the Taylor-Couette flow , Zafar M. Malikov, Farrukh Kh. Nazarov, , Murodil E. Madaliev, and Vestnik Tomskogo Gosudarstvennogo Universiteta Matematika I Mekhanika, 2022 Swirling flows of fluids and gases are an integral part of many complex flows which are widely encountered in nature and technology. The working process of numerous technical devices (cyclones, vortex combustion chambers, air separators, gas and steam turbines, electric machines and generators, etc.) is generally determined by the laws of hydrodynamics and heat exchange of rotating flows. The problem of deriving general laws for a turbulent flow in the field of centrifugal forces provokes considerable scientific interest since it belongs to an underdeveloped field of hydromechanics. Therefore, mathematical modeling of swirling turbulent flows is still an urgent problem. In this paper, a comparative analysis of the advanced turbulence models for the Taylor -Couette flow is carried out. For this purpose, the linear turbulence models (SARC and SST-RC), the Reynolds stress method SSG/LRR-RSM-w2012, and a two-fluid model are used. The results obtained using these models are compared with each other and with known experimental data and direct numerical simulation results. The numerical results calculated with the use of turbulence models for the Taylor-Couette flow confirm that almost all the models adequately describe velocity profiles. However, they yield different turbulent viscosity values and, as a result, different friction coefficients. A comparison of the numerical results shows that the friction coefficient calculated using a two-fluid turbulence model is the closest to that obtained experimentally.
