Advanced Hydrodynamics Problems in Earth Sciences

ISBN-13: 9783031230493 / Angielski / Twarda / 2023 / 234 str.

Tatiana Chaplina

Opis

This book explains the dynamics of natural systems – the geosphere, hydrosphere and atmosphere – and their interactions, along with the human contribution to naturally occurring processes, which is one of the most urgent and practically important scientific problems of our age. The widespread use of sophisticated, tremendously powerful supercomputers now allows us to model complex phenomena that were previously inaccessible for analysis. Further, the introduction and advancement of a new generation of geophysical instruments – remote observing systems installed on ships, aircraft and satellites – make it possible to gather huge amounts of objective, representative data. The articles presented here offer valuable insights into the laboratory modelling of geo-environments and testing of newly developed physical and mathematical models.

Spis treści

Advanced Hydrodynamics Problems in Earth Sciences 1. Soboleva E. B. Mitigation of Rayleigh-Taylor Convection in a Porous Medium by Initial Periodic Fluctuations Abstract. Numerical simulation of gravity-driven convection in a porous medium in application to geological problems is conducted. A stability of two-layered fluid system with the lower layer being a pure fluid and the upper layer being the fluid with dissolved admixture is analyzed. A growth of instability is triggered by initial periodic density fluctuations at the interface. Peculiarities of convective flows and mass transfer depending on the wave length of disturbances are investigated. As obtained, if the wave length of disturbances is of the order of average double width of convective fingers originated under random fluctuations, those disturbances can lead to mitigating of convection. In this case, the prescribed motion cannot develop freely and transit to stochastic mode, that leads to its deceleration and a decrease in convective mixing. Keywords: porous medium, dissolved admixture, Rayleigh-Taylor convection, convective mixing, periodic disturbances, num 2. Kistovich A.V. Viscose mutual involvement of moving contacting liquids Abstract. The presented article deals with the problem of introducing characteristic scales of the velocity field during oil product spills on the water surface. The model problem is solved in the case of a flat contact boundary between an oil product, water and water. The coefficients of mutual involvement of each other in the movement of the mentioned media are determined. Expressions for characteristic dynamic viscous scales are also given. Quantitative estimates are given for spills of specific grades of oil and mineral oils. Keywords: Spreading, Involvement coefficient, Dynamic and Kinematic viscosities, Velocity field. 3. Fedyushkin A.I., Rozhkov A.N. Numerical simulation of a drop collision with an obstacle Abstract. The paper considers the dynamics of the spreading liquid droplets after impact on a solid surface. The dynamics of a drop falling on a solid surface is shown using numerical simulation based on the solution of 2D and 3D Navier-Stokes equations for a two-layer liquid-gas system. The results of numerical simulation are compared with experimental data. Key words: numerical simulation, Navier-Stokes equations, two-phase liquid system, droplet, spreading, coalescence 4. Kravtsova A.Yu. Methods of cavitation flows investigation Abstract. The review is devoted to the description of experimental methods for the study of hydrodynamic cavitation in laboratory conditions. At the moment, the optimal methods for studying cavitation flows are non-contact measurement methods. The high-speed visualization allows analyzing the evolution of cavitation bubbles and cavities simultaneously with the dynamics of the development of large-scale structures in the flow over quite long period of time. The particle image velocimetry (PIV) method serves to obtain correct quantitative values of components of average velocity and statistical moments of velocity up to and including the third order. Keywords: methods of cavitation flows investigation, Pitot tube, visualization, particle image velocimetry (PIV), tomo-PIV. 5. Kumakshev S.A. Modeling of a ring wave system source using satellite surveillance Abstract. Natural (or man-made) phenomena sometimes occur in the Earth's atmosphere and on the surface of the World Ocean, the development of which can produce a danger to people. In order to monitor such phenomena, it is necessary to provide satellite surveillance of the Earth's surface from the spacecraft. The space experiment "Uragan" (Hurricane) is dedicated to this goal. It consists in photographing such phenomena from the ISS. However, after fixing the origin of such a phenomenon, it is necessary to predict its further development. To do this, it is necessary to propose a physical model and build a mathematical model of the phenomenon on its basis. In this article, based on a snapshot of the ring wave system near Darwin Island in the Pacific Ocean, such work has been carried out. Based on the results of multivariate calculations, it was possible to bring the calculated wave system closer to the one depicted in the photograph. This made it possible to verify the mathematical model and evaluate the physical parameters of the wave source. Keywords: Ring Wave System in the Ocean, Modeling of Natural Phenomena, Space Experiment "Uragan" (Hurricane). 6. Kotov M.A., Shemyakin A.N., Solovyov N.G., Yakimov M. Yu. Convective flame of an optical discharge with a decrease in the gravitational acceleration Abstract The results of numerical simulation of convective plume oscillations from a heat source concentrated in space and equivalent to a continuous optical discharge in xenon of high-pressure are presented. Different values of gravitational acceleration were taken. The calculated dynamic distributions of temperature around a small ellipsoidal heat release zone demonstrate the toroidal vortices formation in the convection zone, which leads to the appearance of pulsations. Self-actvity of optical discharges, which leads to the instabilities under consideration, occurs due to the convective plume, which is the result of diffusion heat transfer and thermogravitational convection. When the value of the gravitational acceleration changes, the pulsation frequency and the radius of the heated zone change. Their mutual correlation is shown. The advantages of such a heat source for determining the value of gravity are described. Keywords: laser sustained plasma, hydrodynamic convection, gravity change 7. Pashkov I.I., Shishkin F.A., Zhelezova S.V. Effect of barrier discharge plasma treatment on winter wheat seed germination Abstract The effect of barrier discharge treatment on germination rate and germination energy of winter wheat seeds was studied. Various modes of seed treatment were investigated at discharge frequencies from 1 to 9 kHz and treatment times from 30 to 180 seconds. The germination capacity of seeds of control and treated batches was determined when germinating on wet filter paper. Out of nine seed treatment scenarios, the optimal one was chosen (frequency 1 kHz and treatment time 30 s), which allows increasing germination by 4%. Seed treatment with barrier discharge plasma can be used to increase seed germination in agricultural production. Key words: Barrier discharge, Winter wheat, Germination rate, Seed treatment. 8. Pashkov I.I., Kotov M.A. On the treatment of seeds with cold plasma to improve germination processes Abstract In recent decades, many scientific studies have been carried out that show that plasma seed treatment is unique in its set of properties and environmentally friendly for the disinfection of seeds of various crops, such as wheat, beans, corn, soybeans, barley, peanuts, rice, etc. This method can reduce the use of agricultural chemicals and have a high potential for applications in organic farming. This paper describes the basic concepts and main principles of plasma processing methods and their interaction with seeds. The effect of cold plasma treatment on seeds is explained, various approaches are presented, and some installations for plasma generation are given. Although plasma seed treatment is a relatively new area of research, and the complex mechanisms of the occurring interactions are not fully understood, this method has great prospects for the future. Keywords: seed, grain, germination, cold plasma, corona discharge, barrier discharge. 9. Kistovich A.V. Non-potential waves on the surface of stratified liquid Abstract. In the presented article, the problem of non-potential surface waves description propagated on the surface of stratified liquid is considered. The vorticity of the flow is due to displacement of liquid particles of inhomogeneous liquid in outer gravitational field. It is shown that only the surface wave of finite amplitude generates the internal gravity waves and creates interaction between processes occurring on the surface and in the liquid depth. In infinitesimal limit, no mutual generation has place. Calculations of the characteristics of surface waves of finite amplitude and the vorticity generated by them are presented. Keywords: Surface waves, Internal gravity waves, Stream function. 10. Zapevalov A.S. Scattering short hydroacoustics wave in the presence of long surface –waves Abstract. The presence of long waves leads to a change in the local angle of incidence of acoustic waves on the sea surface. The skewness of the surface slopes leads to the fact that the influence of long waves will differ when probing in the upwind and crosswind direction. Corrections to the scattering coefficient calculated for the situation when resonant waves propagate over a flat surface are obtained. Two types of corrections are considered for sinusoidal waves and for waves with an asymmetric slope distribution. It is shown that at high wind speeds, if the sounding is carried out by an acoustic wave with a length of 0.1 m, at incidence angles of 25°-35°, the correction reaches 100 %. With an increase in the angle of incidence or an increase in the length of the acoustic wave, the correction decreases. The correction of the second type caused by the skewness of the slopes is noticeably smaller. It is advisable to take it into account only at incidence angles of 25°-35°. Keywords: Acoustic Waves, Resonant Scattering; Wind Waves, Sea Surface Slope 11. Kotov M.A. On the determination of diffuse reflectance of PTFE Abstract PTFE has a high diffuse reflectance, especially in the ultraviolet region. The papers describe aspects of its use as an internal material of the cavity of UV air purifiers to improve irradiation and increase the productivity of such devices. This paper provides a brief overview of the main properties of the material. In particular, data on the diffuse reflectance in the spectral range 125-2500 nm from various sources are given. Keywords: PTFE, diffuse reflectance, lambertian reflector, UV air purifier 12. Pakhnenko V.P. Features of admixture dynamics in the fluid depth for complex vortex with free surface Abstract. A processing method for experimental data on the propagation of a marking admixture in the vortex flow column is developed. The correctness of the created programs and the benefits of their use are demonstrated. Based on the used programs, new data on the structure of the isolated central column, where the admixture intensely penetrates the liquid thickness, are obtained. The data obtained are in good agreement with previously obtained results for other types of marking admixtures. Keywords: vortex flow, marking admixture, experimental research, software processing, image, vector graphics 13. Ponomarev M.G. Experimental validation of novel physical model for improvement of sensing 3-dimensional fluid flow loads and responses in real sea conditions with South Western Mooring Test Facility (SWMTF) CEO, Director, Founder, Cambridge Research and Consultancy, United Kingdom. Abstract Tri-axis load cells (transducers) are widely used in modern engineering systems to measure three-dimensional forces (strains). This paper deals with the design, calibration and analysis methodology of the tri-axis load cells, considering them in specific installation South Western Mooring Test Facility (SWMTF) as a key instrument to measure the mooring leg tension in its x-, y- and z-component for wave energy device development. Within the study a model has been developed for cross-validation of a three-component system. Keywords: mechanical response to fluid flows; force; sensors; strain condition monitoring; transducers; tri-axis load cell sensors; vector load sensors; multi-axis load cell sensors; calibration; precision; reliability; smart sensors; enhance precision; overcoming sensor degradation. 14. Ponomarev M.G. A novel physical model to enhance precision and performance of 3-dimensional force sensors Abstract 3-dimensional force (load) sensors (transducers) are widely used in modern robotics (including tactile feedback for artificial arm, artificial leg, prosthesis), medical cell tensile experiments, cell mechanical research ([48], [49]), engineering systems to measure three-dimensional forces (feedback strains). For research of 3-dimensional strain force feedback due to fluid flow pressure developed new physical model. During validation via application of this novel method to the SWMTF (South Western Mooring Tests Facility) 10 times precision increase was obtained for the 3-d force readings. The method is effective for wide range of measuring equipment based on vector sensors including electronic (strain gauge), piezoelectric, fiber optic load sensors, hydraulic, mechanical (in proving rings) load cells. In particular, the developed method is very effective for accelerated (fast) data processing of loading measurements to achieve real-time sensor-guided robot motions (including those for industrial robot arm, real-time actuators). Keywords: mechanical response to fluid flows; force; sensors; strain condition monitoring; transducers; tri-axis load cell sensors; vector load sensors; multi-axis load cell sensors; calibration; precision; reliability; smart sensors; enhance precision; overcoming sensor degradation.

O autorze

Chaplina Tatiana, Doctor of Physical and Mathematical Sciences, graduated from the Faculty of Physics at Lomonosov Moscow State University. Her research interests are vortices, waves, impurities, mechanics of multiphase media, physical and mathematical modelling. She is Author of more than 250 works and holds three patents, and is Director of Quaternion Publishing House.