Hydrodynamic Studies Research Articles

Hydrodynamics Analysis of Mixing Process in Fermenter

The perfect mixing process ensures the ideal substrate conditions for microorganisms to live to produce ethanol in the fermenter. The critical factors that affect the mixing process are the agitation speed, baffle configuration, and the impeller type. The Computational Fluid Dynamics (CFD) software can make the study of fermenter hydrodynamics more convenient due to the cost savings of expensive apparatus and less time-consuming. This study aimed to examine the hydrodynamic characteristics of a fermenter using the ANSYS FLUENT 2021 R1 software and its validation. The hydrodynamics of the mixing process in the dual-pitched blade impeller bioethanol fermenter in agitation speeds of 200 to 1000 RPM and the effect of baffles were observed by simulation and experimentally. The realizable k-epsilon turbulence model and the Eulerian volume of fluid mixture multiphase model were used in this CFD simulation. The simulation results were relatively close to the experimental with similar flow patterns and low mixing time error, which is 7.9% on average. The results show that the higher the agitation speed, the higher the torque, power, and shear stress. The increasing agitation speed caused the lower mixing time. A faster mixing time was obtained in the fermenter with no baffle configuration.

Methodology of experimental filtration studies (releases) from high-pressure inter-salt productive deposits of industrial lithium-bearing brines of the hydrogeological halogen-carbonate formation of the Siberian platform

It is known that all our knowledge about the industrial brines of the Siberian platform was obtained while drilling wells for oil and gas whereas targeted studies of brine-bearing horizons in deep wells for hydrocarbons are hardly conducted. One of the reasons is the high daily rate in the drilling cycle resulting in carrying out strictly limited additional works not related to drilling. Meanwhile, the geological results including the forecast, the estimation of the calculated parameters of the section productive intervals, the exploration and development methodology of deposits of industrial metal-bearing brines with abnormally high reservoir pressure directly depend on the data of the hydrodynamic studies. Today, large companies – subsurface users of the south of the Irkutsk region are tasked to determine the methodology of short-term pilot releases, which provides correct input data for reserve calculation of industrial brines of natural inter-salt carbonate fractured reservoirs of the hydrogeological halogen-carbonate formation. To determine a reliable permeability coefficient under the experimental filtration work, it is necessary to achieve a quasi-stationary filtration mode. The optimal mode is an intermittent one of brine release with a constant flow rate at the same time intervals with a continuous recording of pressure changes by the telemetry system. The results of pilot releases implemented at the Znamenskiy site of the Angara-Lena deposit of industrial lithium-bearing brines have been considered. The release methods enabling the performance of experimental filtration work in a short time, and applicable in well construction for hydrocarbon production have been proposed. Surface users can carry out the research using the proposed methodology in the case when the well bottom unexpectedly opens a brine formation with an abnormally high reservoir pressure of the fluid system. The implementation of experimental filtration work employing the described methods allows the subsoil users to substantiate the resource base of industrial brines and the elements in them including lithium, rubidium, cesium, bromine, iodine and other rare, trace elements and mineral salts.

ANALYSIS OF HYDRODYNAMIC INTERACTION OF WELLS BASED ON DETERMINATION OF PRODUCTION AND INJECTION COMPENSATION BALANCE USING THE EXAMPLE OF RESERVOIR — BARREM CLINOFORM OF PRIOBSKY SEDIMENTATION BASIN

Abstract. Long-term development of oil fields using a reservoirpressure maintenance system by injecting water into the formation leadsto a number of features of well operation identified during fieldgeophysical and hydrodynamic studies. The combination and processingof parameters characterizing the field development indicators and theoperation of wells in the injection-production section make it possible toconduct a qualitative assessment of the processes occurring in the subsoil.The article describes the procedure for determining possible sources ofwater flooding of oil wells in a large multi-zone field in Western Siberia.In order to determine the compensatory balance of production andinjection taking into account the regional stress characteristic of the field,calculations were made using a geometric figure in the form of an ellipse.The drainage zone described in this way does not contradict the ratio ofthe number of injection and oil wells in the nine-point developmentsystem. The analysis of geological and field information and hydrodynamicstudies made it possible to identify a difference in the signs of increasedwater cut of the product with uncontrolled growth of a man-made fracturein the direction of regional stress and when overlying horizons, which areinterbedded with water-saturated sandy bodies formed under the Bystrinskyclay pack during the regression cycle of sedimentation, were included inthe development. From the point of view of the analysis results, one of thepossible reasons for the development of man-made fluid contacts betweenthe injected and formation water of the overlying formation is a violationof the cement support behind the production string of the injection well.And as a result, there is a top-down flow in the production wells. Theoccurrence of disturbances in the cement support is a technical reason andcan be associated with technological processes carried out on injectionwells during operation, or imperfection in adhesion during insulation andtechnical work. The methods used in the article to determine thehydrodynamic interaction of wells and the signs of formation ofinterformation fluid contacts made it possible to assess the possiblereasons for the increase in water cut in the complex, low-permeability oilreservoirs of the Goteriv-Barremian clinoform of the Priobskysedimentation basin.

Entropía y análisis de Hurst para la determinación de la complejidad de series temporales de flujo bifásico

In this work is presented a hydrodynamic and mass transfer study using the computational fluid dynamic (CFD) for typical experimental measurements and theoretical calculations for pyrite (FeS2) dissolution in acid media using ozone as an oxidizing agent, which occurs in a laboratory glass reactor. The hydrodynamics for the reactor employed, was evaluated with the Navier-Stokes equations (κ-ɛ) RNG turbulence model and the VOF multi-phase model. The results of the hydrodynamic simulation study show that the reactor can operate at a speed range of 1.2 to 4.4 m/s at a total pressure of 12.5 Pa; the Reynolds numerical profile indicates that the flow has a turbulent behavior inside the reactor. For the mass transfer simulation, the model of finite velocity-Eddy dissipation was used for solving the kinetic of the reaction, and was performed for 3 different particle fractions: -106 +75 µm, -38 +25 µm and -25 µm. The simulation results present satisfactorily differences of 17%, 13% and 2% respectively, in comparison with experimental data for pyrite dissolved.

Multi-PTO Wave Energy Converter for Low Energetic Seas: Ensenada Bay Case.

The paper presents a wave energy converter concept to harvest energy at Ensenada Bay, Mexico. The study area can be classified as a low energy sea due to the mean wave power being around 10 kW/m; the wave conditions are significant wave height of 0.5 to 2.5 and peak period of 5 to 20 s. The wave energy converter is formed by a torus buoy and anchored to the sea bottom by four connection structures distributed every 90°. The connected structures play a piston role, and their response is leveraged to run a power take-off system, for example, a linear or hydraulic system. This work does not focus on designing the power take-off system; therefore, it is simplified as linear damping, and an iterative process calculates its value. The hydrodynamic buoy study is made on the frequency domain with Nemoh BEM solver and the power absorption on the time domain with the WEC-Sim code. The capture width ratio is used to evaluate the wave energy converter performance and is a key factor in choosing the optimal size. The wave energy converter captures an average of 20% of the available energy and is well-fixed between periods 8 and 16 s. The present study achieves its target: providing a wave energy converter system to operate under site wave conditions.

Hydrodynamic studies of a 15 MW semi-submersible FOWT to assess the suitability of the inclusion of a damper system

Floating Offshore Wind Turbines (FOWT) can exploit the high energy density found in the offshore environment, with turbines now reaching up to 15 MW in size. At the same time, however, the energetic environment and the massive size of the device present significant challenges in the motion stabilization and mooring system. To overcome these challenges, a tuned mass damper (TMD) has been considered for integration in the FOWT for peak motion reduction. This paper investigates the baseline responses including motion, dynamic response, and tensile loading of the mooring line for a 15MW FOWT on a semi-submersible platform without TMD to identify the damageable motion and the impacts of the TMD on the motion response under wave-wind environmental loadings. The comprehensive analysis is conducted in a package for the dynamic analysis of offshore marine systems, named as Orcaflex. The dynamic and motion characteristics of the 15MW FOWT are analysed and compared under different environmental parameters. The wave and wind parameters are quantified by the 20-years statistical data of the Celtic Sea including both operational and extreme conditions (with a 50-year return period). Subsequently, the key parameters of TMD are investigated by configuring different combinations of mass, damping coefficients and stiffnesses. The preliminary results of the study show that the TMD system can successfully mitigate extreme motion characteristics, however this is strongly dependent on damping properties. Unsuitable TMD designs may increase the motion responses of FOWT and the tensile loading on the mooring line. Therefore, the TMD properties have to be adjusted based onsite environmental conditions). With this consideration, an active TMD with changeable damping properties will be conducted in future research.

CFD Simulation of Air-Glass Beads Fluidized Bed Hydrodynamics

The hydrodynamic behaviour of air-glass beads bubbling fluidized bed reactor containing spherical glass beads is numerically studied, using OpenFoam v7 CFD software. Both Gidaspow and Syamlal-O'Brien drag models are used to calculate momentum exchange coefficients. Simulation predictions of pressure loss, bed expansion rate, and air volume fraction parameters were compared and validated using data, existing in the literature obtained experimentally and performed by other numerical softwares. Pressure loss and rate of bed expansion were calculated with relative root mean square error (RMSE) equal to 0.65 and 0.095 respectively; Syamlal-O'Brien model is considered more accurate than Gidaspow model. Hence, numerical model reliability developed on OpenFoam was also proved. The hydrodynamic aspect study of the fluidized bed reactor was then performed, to analyse the impact of inlet air velocity (U) on particles motion. It was revealed that with U increment, air and glass beads axial velocities increase in the reactor centre and decrease in the sidewalls. Thus, a greater particle bed expansion is induced and the solid particles accumulated highly on the reactor sidewalls. In general, with the increase of U, the solid volume fraction decreases from 0.63 to 0.58 observed at 0.065 m/s and 0.51 m/s, respectively.

Experience in the development of a system for repeated prosthetic heart valves

The failure of heart valve bioprostheses, requiring repeated intervention to replace them, is a serious drawback that narrows the scope of such devices. The present study demonstrates the experimental investigation of a medical device designed to partially solve the problem of repeated interventions on heart valves, primarily with an emphasis on reducing the duration and trauma of such procedures due to the sutureless balloon implantation method of the «valvein- valve» method.Material and methods. The paper presents a series of in silico, in vitro and in vivo experiments to evaluate various aspects of the device under development. Numerical modeling of the final shape setting to the supporting frame of the heart valve prosthesis to select the most promising concept for prototyping was carried out in the Abaqus/CAE (Dassault Systèmes, France) based on the finite element method. The selected optimal support frame model was prototyped in the form of a series of prosthesis samples of four standard sizes for hydrodynamic studies of quantitative characteristics in vitro. The study was carried out in the Vivitro Labs unit (Vivitro Labs, Canada), imitating the physiological mode of the heart, the prostheses were examined for the mitral position. The developed prototypes of the device were supplemented with related products, an implant holder and a balloon catheter, after which the proposed method of sutureless fixation was validated in an in vitro implantation procedure on a bovine heart model and a series of in vivo (n = 3) chronic experiments on animals.Results. In the course of numerical simulation, it was shown that in Model No. 3 of the supporting frame of the prosthesis, the smallest stresses occur – with an amplitude of up to 490 MPa. For other concepts (Models No. 1 and No. 2), this indicator was significantly higher, 543 and 514 MPa, respectively. Prototypes obtained on the basis of the selected shape of the support frame demonstrated satisfactory hydrodynamic characteristics: effective hole area 190-261 mm2, regurgitation volume 6–9 ml/cycle, average transprosthetic gradient 4.4–6.4 mmHg, depending on size. The study of the technology of sutureless balloon implantation in an in vitro model of the heart and the subsequent chronic experiment on sheep confirmed the main idea of the system – the possibility of a significant reduction in the duration of repeated prosthetics. It has been shown that the time of suture implantation of the “classic” frame prosthesis of the mitral valve is 23–29 minutes, with a total access time of 41–52 minutes. When implanting the experimental device, the sutureless prosthesis itself took 4–6 minutes, access time 24–29 minutes. At the same time, one-month results of an echocardiographic study of the operation of the prosthesis demonstrated satisfactory hemodynamics.Conclusions. This work demonstrates a consistent series of tests of the system being developed for repeated heart valve replacement, which substantiates some design solutions, confirms the effectiveness and viability of the chosen approach to sutureless minimally invasive implantation.

Hydrodynamics and effect of velocity on particle filtration due to bridging in water-saturated porous media using CFD-DEM simulation.

Particle bridging owing to the confinement of the pore structure affects the transport and retention of particles in porous media. Particle motion driven by gravities were well investigated, whose filtration is mainly affected by the ratio of the particle diameter to the pore throat size of the medium. However, particles whose motions are driven by the fluid is essential to be investigated for particle separation from the carrying fluid. In this study, the motion of particles was driven by the liquid when passing through a water-saturated porous medium. The fluid-particle flow in a porous medium was modeled using computational fluid dynamics-discrete element method. The motion of particles in the slurry was traced in the porous medium, which enabled particle clogging to be directly precited by the interaction between the particles and pore surfaces by assessing the exact location of each particle. The pressure and flow field of the liquid were investigated, and the variation in flow path owing to particle clogging was predicted. The hydrodynamic study also showed that the Stokes number and particle concentration determined the particle clogging at the pore throats of the porous medium. Increasing the fluid velocity of particles such that the Stokes number was almost equal to 1 increased the separation efficiency of particles. Further increasing the fluid velocity reduced the residence time, which reduced the separation efficiency of the particles.

Photo-Fenton remediation of textile wastewater in fluidized-bed reactor using modified laterite: Hydrodynamic study and effect of operating parameters

There has been an increased interest for the use of naturally available catalysts in Fenton oxidation procedures. Nevertheless, the potential of laterite soil for the removal of aqueous pollutants via Fenton based technique has not been exhaustively explored. The fluidized bed photo Fenton approach was used in this study to treat textile wastewater with the goal of reducing total organic carbon (TOC) in the wastewater. Thermally modified laterite soil was used as a catalyst in the photo-Fenton process. Severalcharacterizationtechniques including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD) and X-ray photo-electron spectroscopy (XPS), were used to gain insight into the characteristics of a modified laterite catalyst. The application of this catalyst resulted in a significant reduction of total organic carbon (TOC) present in the textile wastewater. Specifically, a TOC reduction of 83% was observed after a reaction period of 100 min, at pH 3, 10 mm of bed height, 30 mM of H2O2 concentration, and a recirculating feed flow rate of 170 ml/min. Kinetic and hydrodynamic investigations were also carried out to have a better understanding of the catalytic processes occurring inside the fluidized-bed reactor. A first-order kinetics could potentially be used to explain the photo-degradation of textile effluent. Up to three successive oxidation cycles, laterite exhibited notable catalytic stability attributed to lesser surface site deactivation. A cost-benefit analysis of the fluidized bed photo-Fenton technique for treating textile effluent was also performed. The fluidized-bed Fenton approach may be a feasible option for treating wastewater containing different colours because of its low operating costs and low environmental effect.

Numerical simulation of planing motion and hydrodynamic performance of a seaplane in calm water and waves

ABSTRACTThe high-speed motion of a seaplane involves the coupled hydrodynamic and aerodynamic effects. The suction force, pressure, free surface and motion of the seaplane model were numerically investigated to understand the characteristics of the seaplane's planing motion. The study utilized the SST-DDES turbulence model to analyse the coupled hydrodynamic and aerodynamic effects. Overset mesh method and rigid body motion were employed to simulate the high-speed and substantial motion of seaplane. The volume of fluid method (VOF) was used to capture and sharpen the interface between water and air. First, verification and validation (V&V) were performed by comparing the results with those of the towing tank experiments. Second, the air-water entrainment in calm water and free surfaces were presented, and the pressure distribution on the seaplane was analysed and discussed. Numerical simulations were performed while considering the wave parameters of different velocities, wavelengths, and wave heights. The accelerations of the fore, aft, and centre of gravity of the seaplane demonstrated the presence of the suction effect. The evolution of the air-water entrainment at the bottom of the fuselage was observed. The investigation of suction characteristics revealed that the aerodynamic force in waves plays a substantial role in influencing motions of the seaplane.HighlightsThe study of hydrodynamics and aerodynamics of seaplanes is interdisciplinary. The numerical schemes, including a SST-DDES turbulent model, overset mesh method, and volume of fluid (VOF) method, have proven to be effective and accurate for simulating the motion of the seaplane and flow field characteristics.The greater the speed and wave height, the faster is the motion of the seaplane and the greater are peak and trough values of the pitch. As the wavelength increased, the peak value of the motion decreased gradually.The accelerations of the aft, fore, and centre of gravity of the seaplane in the waves exhibited significant periodicity. The peak value of the acceleration at the aft was the largest, whereas that at the centre of gravity was mild, and the peak value of the acceleration at the centre of gravity was greater than that at the fore. The acceleration indicates that suction at the aft of the seaplane hinders the takeoff during the planing motion.

Coolant Hydrodynamics in the PWR Reactor Core with TVS-Kvadrat of Various Designs

. The paper presents the results of experimental studies of the hydrodynamics of the coolant in the core of the PWR reactor with fuel assemblies “TVS-Kvadrat” of various designs. Experimental studies of hydrodynamics consisted in studying the velocity fields and the process of cross-flow of coolant between adjacent fuel assemblies “TVS-Kvadrat” of various designs in homogeneous and mixed cores on large-scale experimental models, including fragments of two adjacent fuel assemblies “TVS-Kvadrat” and a gap between them. The test models differ in the number of installed grids, this is due to the fact that in a homogeneous core the hydraulic load along the height of the fuel assemblies is identical, and in a mixed core the hydraulic load is uneven due to the different number of installed grids. The hydrodynamics of the coolant has been studied on an aerodynamic open-loop based on the theory of hydrodynamic similarity, using individually calibrated pneumometric sensors. Based on the data obtained, the fields of local axial and transverse velocities in various sections along the length of the studied section of the test models have been constructed. The fields of local dimensionless transverse and axial flow velocities in the fuel bundles and the gap between the fuel assemblies “TVS-Kvadrat” of the PWR reactor core have been studied. Peculiarities of the process of transverse flow between adjacent “TVS-Kvadrat” of a homogeneous and the mixed core of the PWR reactor have been revealed. The results of experimental studies have been transferred to the developer of “TVS-Kvadrat”, that is JSC “Experimental Design Bureau of Mechanical Engineering named after I. I. Afrikantov”, for further use in justifying the design and operating modes of a nuclear power plant.

An experimental and numerical hydrodynamic study on the Argentinian fishing vessels

The purpose of this work is the validation of the hydrodynamic resistance for a small fishing vessel providing more details about the ship’s hydrodynamics. The selected ship is a traditional vessel that has been sailing in Argentina for more than 20 years without a previous numerical resistance evaluation. Because of the absence of previous numerical optimization, the ship might be a non-efficient vessel from a consumption, operating and polluting point of view. For this reason, in order to bring a more detailed evaluation of the flow around this hull, numerical studies are carried out with the open source OpenFOAM code and validated with experimental results obtained at the University of Buenos Aires towing tank. Reynolds Averaged Navier Stokes (RANS) method together with volume of fluid (VOF) are used for the numerical procedure. Once the resistance results are validated, the total resistance coefficient is split into viscous and wave coefficients in order to provide insight into ship hydrodynamics. Pressure distributions on the hull and wave patterns will be also presented for different ship loading conditions, focusing on the flow around the hull that might give information for a future hull optimization.

Electrocatalytic reduction of Cr(VI) on gold-based electrodes in acidic medium: A systematic approach to chromium detection

In the present research, gold immobilized on different substrates (Au, GC, Pt) was examined to fabricate a Cr(VI) sensor in an acidic medium via reduction reactions. Comparative analysis revealed that Au-Pt electrode exhibited better electrocatalytic activity towards the reduction of Cr(VI) compared to Au, Au-Au or Au-GC electrode, which is emphatically discussed in this article. Specifically, the inner α-Au2O3 species of Au matrix on the catalytic surface played a key role in catalyzing Cr(VI) in the acidic medium. Voltammetric investigations revealed that the concerned electrode process is proton-dependent. From hydrodynamic voltammetric studies, it was found that the reduction reaction follows a multistep reaction mechanism with a single electron transfer rate-determining step over the Au-Pt surface. The Cr(VI) reduction reaction follows 1st order kinetics at the Au-Pt electrode surface, where the standard rate constant (k) was found to be 1.4×10−2 cm−1. The excellent improvement of reduction current over the Au-Pt surface was exploited in the fabrication of the Cr(VI) sensor. The developed sensor detects Cr(VI) ions with a linear dynamic range of 10 to 130 μM, whereas the sensitivity and limit of detection values are 3.21 μAμM−1cm−2 and 2.97 μM, respectively. Overall, the findings highlight the promising performance of the Au-Pt electrode in detecting Cr(VI) ions and provide valuable insights into the underlying catalytic diagnosis.

An integrated satellite characterization and hydrodynamic study in assessing coastal dynamics in Cirebon, West Java

Located on the northern coast of Java Island, the coastal area of Cirebon is an area with rapid population growth and extensively developed as settlement areas, industrial estates, fisheries, agriculture, and public service infrastructures. Coastal dynamics issues have been occurring in the coastal area of Cirebon, which is characterized by significant changes in shoreline position. Moreover, some critical infrastructures are not functioning properly and may cause high maintenance costs and economic loss to the related stakeholders. This study aims to provide a greater understanding of the coastal dynamics along the 73.16 km of Cirebon shoreline through remote sensing and GIS methods supported by hydrodynamic analysis. This study applied coastal characterization, coastal structure identifications, and coastal processes assessments, including erosion and accretion analysis, hydrodynamic and tidal analysis, and inundation projection. The study indicates that some areas have been subject to significant erosion and accretion during the last two decades, with the total lengths of the eroded and accreted shoreline being −21.9 km (35.6%) and ＋39.6 km (64.4%), respectively. Furthermore, the coastal structures significantly influence the coastline’s dynamic and mitigate the negative impacts of coastal floods. Jetty access channels in the west area have caused partial coastal erosion, while the breakwaters in the east area accelerated sedimentation processes and improved the growth of mangroves simultaneously. This study also simulated the potentially inundated areas by 2050 in four scenarios based on projected sea level rise, land subsidence, and extreme wave events. Policies to prevent such potential hazards are needed to avoid negative impacts on the living quality and vital economic sectors. This study provides insight into coastal characterization, potential coastal hazards, and their driving processes in time and space scale for coastal adaptation planning policies and sustainable coastal hazard management and mitigation.

ҚАБАТТА ЖАРЫҚШАҚТЫҢ ТҮЗІЛУІНЕ СҮЗІЛУ КОЭФФИЦИЕНТІНІҢ ӘСЕРІ

Annotation. As the practice of developing hydrocarbon deposits has shown, when extracting oil from multilayer deposits, as a result of numerous hydrodynamic and geological-geophysical studies, separate sections of formations with a more homogeneous structure are identified. In most cases, such formations, as the results of the analysis of the state of development of deposits show, turn out to have sufficiently low filtration and capacitance properties (porosity and permeability), while increasing the volume of hard-to-recover oil reserves. This circumstance of deposits worsens the state of the degree of efficiency of extraction of hydrocarbon reserves from multilayer deposits. In this regard, in order to increase the efficiency of the oil field development process, various measures aimed at intensifying the extraction process from unproductive intervals-formations are very often used in practice. One of the active methods that allow the most complete displacement of oil from the productive reservoir is hydraulic fracturing.Currently, in many oil fields, in order to increase the flow rate of the well, hydraulic fracturing (FRACKING) in various combinations has been actively carried out recently by using both filtered and unfiltered liquids. In this regard, the greatest practical interest is the solution of the problem associated with the establishment of the effect of liquid filtration on the size of the crack opening formed during hydraulic fracturing. The article discusses one of the most common methods of increasing the productivity of wells that open low–permeability reservoirs - hydraulic fracturing (FRACKING). The paper investigates the effect of the liquid filtration coefficient on the width of cracks that are formed during hydraulic fracturing. Formulas for determining the width of cracks in the filter fluid are obtained. The results obtained show that liquid filtration has a significant effect on the width of the horizontal crack opening. Keywords. Borehole, filtration, pressure gradient, permeability, crack, hydraulic fracturing, crack width, crack length, collector.

Productivity of unconventional Senon reservoirs in the north of West Siberia

At the current stage of geological exploration, hydrocarbon deposits have been discovered in complex reservoirs that are "unconventional" in nature. In particular, at the Medvezhye field, according to the interpretation of seismic surveys and the drilling of exploratory wells, a gas deposit was discovered in the Senonian deposits of the Nizhneberezovskaya suite of Upper Cretaceous deposits. The gas deposit of the NB formation of the Medvezhye field is characterised by productive reservoirs, mostly represented by mudstones and opoka-like clays. These rocks are characterized by low filtration parameters. Commercial gas inflows from secondary reservoir openings indicate the presence of fractured rock, as confirmed by core testing, mechanical logging. A comprehensive analysis of hydrodynamic studies of field parameters, such as reservoir pressure, drawdown, flow rate, allows calculating the filtration characteristics of a productive formation. The performance of fractured and mixed pore-fractured reservoirs is determined using induction diagrams and pressure recovery curves, the reservoir hydrodynamic model and methods for improving development in complex "unconventional" reservoirs are refined.

A Comparative and Collaborative Study of the Hydrodynamics of Two Swimming Modes Applicable to Dolphins.

This paper presents a hydrodynamics study that examines the comparison and collaboration of two swimming modes relevant to the universality of dolphins. This study utilizes a three-dimensional virtual swimmer model resembling a dolphin, which comprises a body and/or caudal fin (BCF) module, as well as a medium and/or paired fin (MPF) module, each equipped with predetermined kinematics. The manipulation of the dolphin to simulate various swimming modes is achieved through the application of overlapping grids in conjunction with the parallel hole cutting technique. The findings demonstrate that the swimming velocity and thrust attained through the single BCF mode consistently surpass those achieved through the single MPF mode and collaborative mode. Interestingly, the involvement of the MPF mode does not necessarily contribute to performance enhancement. Nevertheless, it is encouraging to note that adjusting the phase difference between the two modes can partially mitigate the limitations associated with the MPF mode. To further investigate the potential advantages of dual-mode collaboration, we conducted experiments by increasing the MPF frequency while keeping the BCF frequency constant, thus introducing the concept of frequency ratio (β). In comparison to the single BCF mode, the collaborative mode with a high β exhibits superior swimming velocity and thrust. Although its efficiency experiences a slight decrease, it tends to stabilize. The corresponding flow structure indirectly verifies the favorable impact of collaboration.

New Bioretention Drainage Channel as One of the Low-Impact Development Solutions: A Case Study from Poland

In recent years, as a result of intensive urbanisation, a significant increase in the surface of impermeable areas has been observed, which results in changes in the hydrological cycle of catchments. In order to counteract these changes, low-impact development (LID) solutions are increasingly being implemented in urban catchments, including bioretention systems. Taking this into account, a new bioretention drainage channel (BRC) was designed, whose main task is retention, infiltration, and pre-treatment of rainwater. The pilot laboratory tests carried out on two BRC prototypes (K1 and K2) showed that the average rate of reduction of mineral-suspended solids from rainwater was 69% and 57%, respectively, for K1 and K2. Analysing the results of the research, it was found that the bioretention drainage channel is characterised by very high efficiency in removing petroleum hydrocarbons from rainwater, and the reduction rate of these pollutants for both the K1 and K2 channels was close to 100%. In turn, hydrodynamic studies carried out on the model of the urban catchment showed that the implementation of BRCs will reduce the peak runoff by more than 82%, and the maximum flow in the sewage network by 83%.

PEG-Lipids: Quantitative Study of Unimers and Aggregates Thereof by the Methods of Molecular Hydrodynamics.

Understanding the polymorphism of lipids in solution is the key to the development of intracellular delivery systems. Here, we study the dynamics of poly(ethylene glycol)-lipid (PEG-Lipid) conjugates aiming at a better understanding of their molecular properties and aggregation behavior in solution. Those PEG-Lipids are used as components of lipid nanoparticles (LNPs). LNPs are gaining increased popularity, e.g., by their utilization in modern vaccination strategies against SARS-CoV-2. Characterization of the systems is conducted by the classical methods of hydrodynamics in different solvents, such as ethanol and water, which are also commonly used for LNP formulation. We were able to elucidate the structurally associated hydrodynamic properties of isolated PEG-Lipids in ethanol, revealing the typically expected values of the hydrodynamic invariant for random coil polymers. By virtue of the same experimental setting, the PEG-Lipids' behavior in water was as well studied, which is a less good solvent than ethanol for the PEG-Lipids. Our experiments demonstrate that PEG-Lipids dissolved in water form well-defined micelles that can quantitatively be characterized in terms of their degree of aggregation of PEG-Lipid polymer unimers, their hydrodynamic size, and solvation, i.e., the quantitative determination of water contained or associated to the identified micelles. Quantitative results obtained from classical hydrodynamic analyses are fully supported by studies with standard dynamic light scattering (DLS). The obtained diffusion coefficients and hydrodynamic sizes are in excellent agreement with numerical results derived from analytical ultracentrifugation (AUC) data. Cryo-transmission electron microscopy (cryo-TEM) supports the structural insight from hydrodynamic studies, particularly, in terms of the observed spherical structure of the formed micelles. We demonstrate experimentally that the micelle systems can be considered as solvent-permeable, hydrated spheres.