Flow Solution Research Articles

Generalized Solution for Double-Porosity Flow Through a Graded Excavation Damaged Zone

Generalized Solution for Double-Porosity Flow Through a Graded Excavation Damaged Zone

Pressure-dependent large-scale seismic anisotropy induced by non-Newtonian mantle flow

Summary Observations of large-scale seismic anisotropy can be used as a marker for past and current deformation in the Earth’s mantle. Nonetheless, global features such as the decrease of the strength of anisotropy between ∼150–410 km in the upper mantle and weaker anisotropy observations in the transition zone remain ill-understood. Here, we report a proof of concept method that can help understand anisotropy observations by integrating pressure-dependent microscopic flow properties in mantle minerals particularly olivine and wadsleyite into geodynamic simulations. The model is built against a plate-driven semi-analytical corner flow solution underneath the oceanic plate in a subduction setting spanning down to 660 km depth with a non-Newtonian n = 3 rheology. We then compute the crystallographic preferred orientation (CPO) of olivine aggregates in the upper mantle (UM), and wadsleyite aggregates in the upper transition zone (UTZ) using a viscoplastic self-consistent (VPSC) method, with the lower transition zone (LTZ, below 520 km) assumed isotropic. Finally, we apply a tomographic filter that accounts for finite-frequency seismic data using a fast-Fourier homogenization algorithm, with the aim of providing mantle models comparable with seismic tomography observations. Our results show that anisotropy observations in the UM can be well understood by introducing gradual shifts in strain accommodation mechanism with increasing depths induced by a pressure-dependent plasticity model in olivine, in contrast with simple A-type olivine fabric that fails to reproduce the decrease in anisotropy strength observed in the UM. Across the UTZ, recent mineral physics studies highlight the strong effect of water content on both wadsleyite plastic and elastic properties. Both dry and hydrous wadsleyite models predict reasonably low anisotropy in the UTZ, in agreement with observations, with a slightly better match for the dry wadsleyite models. Our calculations show that, despite the relatively primitive geodynamic setup, models of plate-driven corner flows can be sufficient in explaining first-order observations of mantle seismic anisotropy. This requires, however, incorporating the effect of pressure on mineralogy and mineral plasticity models.

Power Flow Calculation for AC/DC Power Systems with Line-Commutated Converter–Modular Multilevel Converter (LCC-MMC) Hybrid High-Voltage Direct Current (HVDC) Based on the Holomorphic Embedding Method

To harness the strengths and mitigate the limitations of line-commutated converter (LCC) and modular multilevel converter (MMC) HVDC systems, the LCC-MMC hybrid HVDC system has been developed. This paper proposes a holomorphic embedding (HE)-based power flow calculation method for AC/DC power systems with the LCC-MMC hybrid HVDC system. Firstly, the methodology involves establishing the mathematical model of the LCC-MMC hybrid HVDC system and its control modes. Subsequently, the HE formulation for the constructed LCC-MMC model is derived using the HE method. The proposed method simplifies the HE formulation using substitute variables, making it adaptable to various control modes. The designed HE formulation facilitates the derivation of the germ solution and the calculation of high-order power series coefficients. A sequential solution flow chart compatible with AC power flow algorithms is constructed to enhance the practicality of the HE method for real-world large-scale systems. The accuracy and effectiveness of the proposed method are verified through numerical tests on the modified IEEE 14-bus, IEEE 57-bus, and large 2383-bus system. The proposed method provides a reliable and efficient solution for power flow analysis in hybrid HVDC systems.

Effect and mechanism of solution flow rate during interfacial polymerization on morphology and performance of hollow fiber membranes

Interfacial polymerization (IP) using m-phenylenediamine and trimesoyl chloride (TMC) is an essential method for producing thin-film composite (TFC) membranes. Nevertheless, IP is highly sensitive to changes in process parameters, especially the TMC solutions flow rate during inside-out TFC hollow fibers (HF) production. Research on the impact of flow conditions (i.e., laminar vs. turbulent flows) of these organic solutions on the final membrane characteristics and corresponding mechanism is still lacking. This research tested different TMC flow rates (0.1–2 mL/min) to produce inside-out TFC HF. With a TMC flow rate increase, (i) the leaf-like structures of the polyamide (PA) layer decreased in size, (ii) the thickness of the PA layer slightly increased, and (iii) the pure water permeability decreased. However, the elemental composition, chemical bonds, and NaCl rejection remained stable. Different fluid regimes are considered to affect the performance of HF membranes by affecting the heat dissipation process during IP reaction. A TMC flow rate in the laminar flow state (i.e., low flow rates) is recommended for synthesizing HFs. The current research provides new insights into the IP reaction mechanism of HF membrane, thus offering valuable guidance to optimize and produce membrane products with better performance.

Modification of Deglycerolization Procedure Improves Processing and Post-Thaw Quality of Cryopreserved Sickle Trait Red Cell Concentrates

Red blood cell (RBC) transfusion is a critical therapy for those with sickle cell disease (SCD). Alloimmunization is frequent for those with SCD and may limit the availability of matched RBC. Cryopreserved RBCs, from family members or donors with a similar RBC antigen profile could provide a viable alternative to avoid further alloimmunization and prevent hemolytic transfusion-related events. However, cryopreserved SCD and Sickle Cell trait (S-trait) donor RBC units suffer from reduced recovery following deglycerolization. This study proposes and tests a modified deglycerolization protocol using an automated cell processor to mitigate RBC loss. Six red cell concentrates (RCC) from donors with S-trait and six control RCCs were glycerolized, frozen (< -65 ºC) and deglycerolized on the ACP 215 using modified parameters (decreased hypertonic solution flow rate (100 mL/min) and hypertonic equilibration delay (120 seconds), and increased NaCl dilution volumes (500 mL). Quality testing included: hematocrit (HCT), hemolysis, indices, extracellular potassium, morphology, osmotic fragility, osmotic gradient ektacytometry, hemoglobin (HGB), and recovery. Canadian standards (CS) indicate that acceptable deglycerolized units for transfusion require a HCT ≤ 0.80 L/L, HGB ≥ 35 g/unit, and hemolysis < 0.8% in 90% of units tested. No significant differences in HGB or RBC recovery were observed between study groups. Significant differences between study groups were identified in osmotic fragility and osmotic gradient ektacytometry parameters. Of the 6 S-trait RCCs, 3/6 units were within the HCT, HGB and hemolysis thresholds set by the CS. The modified deglycerolization protocol provides a path for the routine cryopreservation of S-trait RBCs.

Approximate closed‐form solution of free convection flow past a vertical cone

AbstractThis paper presents a technique to find the closed‐form solution of the boundary‐value problem representing free convection flow past a vertical cone. Partial differential equations that govern the flow are converted into nonlinear ordinary differential equations with the aid of similarity transformations. First, a numerical solution is obtained with the help of the bvp4c package of MATLAB, and then utilizing the numerical solution, the closed‐form solution is obtained. The accuracy of the closed‐form solution is analyzed by the residual technique. Graphs of the residuals of the governing equations indicate that our approximate closed‐form solution closely matches the exact solution.

Novel nanostructure approach for antibiotic decomposition in a spinning disc photocatalytic reactor

Conventional wastewater treatment processes are often unable to remove antibiotics with resistant compounds and low biological degradation. The need for advanced and sustainable technologies to remove antibiotics from water sources seems essential. In this regard, the effectiveness of a spinning disc photocatalytic reactor (SDPR) equipped with a visible light-activated Fe3O4@SiO2-NH2@CuO/ZnO core–shell (FSNCZ CS) thin film photocatalyst was investigated for the decomposition of amoxicillin (AMX), a representative antibiotic. Various characterization techniques, such as TEM, FESEM, EDX, AFM, XRD, and UV–Vis-DRS, were employed to study the surface morphology, optoelectronic properties, and nanostructure of the FSNCZ CS. Key operating parameters such as irradiation time, pH, initial AMX concentration, rotational speed, and solution flow rate were fine-tuned for optimization. The results indicated that the highest AMX decomposition (98.7%) was attained under optimal conditions of 60 min of irradiation time, a rotational speed of 350 rpm, a solution flow rate of 0.9 L/min, pH of 5, and an initial AMX concentration of 20 mg/L. Moreover, during the 60 min irradiation time, more than 69.95% of chemical oxygen demand and 61.2% of total organic carbon were removed. After the photocatalytic decomposition of AMX, there is a substantial increase in the average oxidation state and carbon oxidation state in SDPR from 1.33 to 1.94 and 3.2, respectively. Active species tests confirmed that ·OH and ·O2− played a dominant role in AMX decomposition. The developed SDPR, which incorporates a reusable and robust FSNCZ CS photocatalyst, demonstrates promising potential for the decomposition of organic compounds.

Advanced Computational Framework to Analyze the Stability of Non-Newtonian Fluid Flow through a Wedge with Non-Linear Thermal Radiation and Chemical Reactions

The main idea of this investigation is to introduce an integrated intelligence approach that investigates the chemically reacting flow of non-Newtonian fluid with a backpropagation neural network (LMS-BPNN). The AI-based LMS-BPNN approach is utilized to obtain the optimal solution of an MHD flow of Eyring–Powell over a porous shrinking wedge with a heat source and nonlinear thermal radiation (Rd). The partial differential equations (PDEs) that define flow problems are transformed into a system of ordinary differential equations (ODEs) through efficient similarity variables. The reference solution is obtained with the bvp4c function by changing parameters as displayed in Scenarios 1–7. The label data are divided into three portions, i.e., 80% for training, 10% for testing, and 10% for validation. The label data are used to obtain the approximate solution using the activation function in LMS-BPNN within the MATLAB built-in command ‘nftool’. The consistency and uniformity of LMS-BPNN are supported by fitness curves based on the MSE, correlation index (R), regression analysis, and function fit. The best validation performance of LMS-BPNN is obtained at 462, 369, 642, 542, 215, 209, and 286 epochs with MSE values of 8.67 × 10−10, 1.64 × 10−9, 1.03 × 10−9, 302 9.35 × 10−10, 8.56 × 10−10, 1.08 × 10−9, and 6.97 × 10−10, respectively. It is noted that f′(η), θ(η), and ϕ(η) satisfy the boundary conditions asymptotically for Scenarios 1–7 with LMS-BPNN. The dual solutions for flow performance outcomes (Cfx, Nux, and Shx) are investigated with LMS-BPNN. It is concluded that when the magnetohydrodynamics increase (M=0.01, 0.05, 0.1), then the solution bifurcates at different critical values, i.e., λc=−1.06329,−1.097,−1.17694. The stability analysis is conducted using an LMS-BPNN approximation, involving the computation of eigenvalues for the flow problem. The deduction drawn is that the upper (first) branch solution remains stable, while the lower branch solution causes a disturbance in the flow and leads to instability. It is observed that the boundary layer thickness for the lower branch (second) solution is greater than the first solution. A comparison of numerical results and predicted solutions with LMS-BPNN is provided and they are found to be in good agreement.

Numerical study of binary mixture and thermophoretic analysis near a solar radiative heat transfer

The main focus of the current article is to investigate the two-dimensional boundary layer flow of non-Newtonian fluid induced by a linear stretching surface in the streamwise direction. The flow features of non-Newtonian fluid (i.e. shear-thinning and thickening nature of the fluids) are explored with Carreau fluid model. In addition, thermophoresis, Brownian motion, thermal radiation (with Rosseland approximation), binary mixture and activation enthalpy are also incorporated in fluid model for better analysis of thermal and solutal properties. The mathematical modelling of under consider physical problem yields nonlinear partial differential system. The governing mathematical system is first simplified with scaling transformations for the high Reynolds number and then transformed into non-dimensional ordinary differential system by using the similarity variables. Since the governing mathematical system comprised on nonlinear boundary value problem, thus shooting method is utilized for the numerical solution of the fluid flow governing equations. The obtained results followed the qualitative manners of the previously reported data. The computed results for important physical quantities (i.e. velocity, temperature, and concentration) are presented through graphs and then interpreted physically. It is observed that the boundary layer thickness increased for shear thickening fluids (n>1) while it is reduced for shear thinning fluids (n<1). Also, the temperature of shear thinning fluid is higher than shear thickening fluid. In addition, heat generation and thermal radiations enhance the thermal boundary layer. Thermophoretic viscosity effect reduces the concentration profile significantly in the flow domain.

Risk Assessment of Radial Distribution Systems using Modified Jelly Fish Search Algorithm to analyse the Performance Indices

One of the essential techniques for figuring out Power Distribution System performance is reliability evaluation. With time, the range of methods for assessing reliability has grown, and the distribution system's evolution has also become more intricate. The likelihood of a network failing grows with time once it begins to function, especially if it is used for an extended period. Reliability indices have been evaluated using different algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and various modified versions of algorithms. The Jelly Fish Search Algorithm has been used in various power system applications such as to determine the most cost-effective way to dispatch generating units' loads, integrate Distributed Generation (DG) units, track the maximum power of photovoltaic systems, and determine optimal power flow solutions, among other uses. The performance indices for the Radial Distribution System (RDS) have not been evaluated using JFSA.Variation of performance indices with respect to unavailability has not been discussed in the literature. Here an attempt is made to analyse the variation of the indices with the unavailability. The proposed algorithm is evaluated first on 3 load point radial distribution system and the computations are performed on the popular IEEE-RBTS Bus2 test system. Based on the output it is observed that for the both the systems the behaviour of the indices with respect to the unavailability is in similar fashion. The equations are derived for the performance indices using the Minitab. With the equations obtained the Performance indices values can be predicted for the given unavailability value. It is the better appropriate method for the assessing the performance indices of Radia Distribution System.

Mathematical Solutions of Free Convection Flow of Casson Fluid in Channel with Accelerated Plate

This research develops mathematical solutions for Casson fluid flow with free convective phenomena within channels with an accelerated plate. The study transforms the governing energy and momentum equations into the dimensionless form using appropriate variables. The Laplace transformation is used to acquire analytical solutions. Dimensionless parameters, such as the Prandtl number, Grashof number, accelerated parameter, and Casson fluid parameter, are determined, which are further investigated for their impacts on the flow and thermal behaviour. Visual representations of the mathematical results for velocity and temperature are presented using MATHCAD software through graphical plots. The study observes that fluid velocity increases with higher values of Gr but decreases with increased Pr. Additionally, temperature profiles exhibit a decrease with higher Prandtl numbers and an increase with time. The obtained results are validated by comparing them with published results in limiting cases, showing good agreement, and confirming the accuracy and reliability of the research outcomes.

Characterization of arsenic species by liquid sampling-atmospheric pressure glow discharge ionization mass spectrometry.

A liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source operating at a nominal power of 30 W and solution flow rate of 30 µL min-1 and supported in a He sheath gas flow rate of 500 mL min-1 was interfaced to an Orbitrap mass spectrometer and assessed for use in rapid identification of inorganic and organic arsenic species, including As(III), As(V), monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine in a 2% (v/v) nitric acid medium. Mass spectral acquisition in low-resolution mode, using only the ion trap analyzer, provided detection of protonated molecular ions for AsBet (m/z 179), DMA (m/z 139), MMA (m/z 141), and As(V) (m/z 143). As(III) is oxidized to As(V), likely due to in-source processes. Typical fragmentation of these compounds resulted in the loss of either water or methyl groups, as appropriate, i.e., introducing DMA also generated ions corresponding to MMA and As(V) as dissociation products. Structure assignments were also confirmed by high-resolution Orbitrap measurements. Spectral fingerprint assignments were based on the introduction of solutions containing 5 µg mL-1 of each arsenic compound.

Revitalizing Urban Mobility:A Comprehensive Analysis of Traffic Flow and Sustainable Solutions at the Un-signalized Taxila Intersection

In recent years, traffic congestion has become one of many cities’ most significant financial and ecological concerns worldwide. It also costs citizens a substantial amount of time and fuel. Many experts believe that identifying traffic congestion characteristics is the first step in reducing traffic congestion. This study aimed to determine the extent of traffic congestion and fuel consumption at Taxila Chowk. The research’s primary methodological tools were a traffic volume survey and peak hour volume study using Aimsun software. According to this study, auto-rickshaws, bicycles, motorcycles, and trucks were the most common modes of transportation. Traffic flow is particularly heavy in the morning, noon, and evening hours. It was revealed that the H.M.C. road is the most congestion-prone route compared to the other four routes. Also, the distinctive design of rickshaws and bus stands and the misplacement of fruit and vegetable markets play a considerable role in Congestion. The level of service of the four routes is almost intolerable, and the sole P.O.F. road that offered comparable better services to city commuters is an acceptable illustration. The study has also identified the amount of fuel consumption on each route, focused on the environmental impact of Congestion due to emissions of green gasses, and provided feasible solutions in the form of alternatives.

A hybrid CPU‐GPU paradigm to accelerate reactive CFD simulations

AbstractThe solution of reactive computational fluid dynamics (CFD) simulations is accelerated by the implementation of a hybrid central processing unit/graphics processing units (CPU/GPU) Finite Volume solver based on the operator‐splitting strategy, where the chemistry integration is treated independently of the flow solution. The integration of ordinary differential equations (ODEs) describing the finite‐rate chemical kinetics is solved by an adaptive multi‐block explicit solver on GPUs, while the load of the fluid solution is distributed on a multicore CPU algorithm. The resulting speed‐up for reactive CFD simulations is up to 10; the performance gain increases with the size of the mechanism. The proposed implementation is general and can be applied to any CFD problem where the governing equations for the fluid transport are coupled with an ODE system. Code validation is performed against reference solutions on a selection of test cases involving reacting flows.

Nonlinear dynamics of dissipative water conveying SWCNT/MWCNT/Ferro nanofluid subject to radiation: Thermal analysis by linear slope regression

Carbon nanotubes have gained significant attention due to their unique properties like small dimensions, high thermal conductivity, and unique architecture. These nanotubes have enormous potential in various fields such as nanomedicine, mechanical compound materials, sensor devices, bio-sensors, and many other applications. The present study investigates the impact of adding nanoparticles such as iron oxide (Fe3O4), single-walled carbon nanotubes (SWCNT), and multi-walled carbon nanotubes (MWCNT) on magnetohydrodynamics (MHD) oscillatory water-based flow over a porous medium. The aim is to examine the effect of heat and mass transfer rate and radiative viscous dissipation that interacts with Fe3O4 nanoparticles and carbon nanotubes. The governing equations of the dynamic nanofluid systems are transformed into a set of coupled nonlinear partial differential equations through suitable dimensionless transformations and further converted into ordinary differential equations by taking appropriate solutions for oscillatory-type nanofluid flow. The homotopy perturbation method is applied to solve the governing equations with oscillatory boundary conditions and the solution is also compared with the numerical solver bvp4c. The rate of increase in the temperature and Heat Transfer are computed by the linear slope regression method and results are computed for nanoparticles SWCNT, MWCNT, and Ferro. Also, Skin friction and rate of heat transfer are computed and compared for the nanoparticles with varying Peclet and Eckert numbers. The velocity profile and temperature profile of SWCNT/MWCNT/Ferro nanofluids are being compared. The heat transfer rate is observed to be high for Ferro nanoparticles compared to SWCNT and MWCNT.

Legendre wavelet integration operational matrix method for the numerical solution of unsteady MHD nanofluid flow between moving parallel plates

This study proposes a novel method based on Legendre wavelet integration operational matrix for solving a system of nonlinear ODE’s to model the two-phase, unsteady nanofluid flow and heat transfer between parallel plates in presence of magnetic field. To validate the applicability of proposed method, system of nonlinear BVP with exact solutions is employed as a test problem. Test problem results are compared with exact solution, and other numerical methods. The governing equations were then changed using similarity transformation into a set of nonlinear ODE’s. . Following this, the LWOMM is applied for the proposed problem. Findings demonstrated that, for a constant Reynolds number, skin friction coefficient value increases with rising Hartmann and squeezing numbers. Furthermore, it is demonstrated that Eckert number is a reducing function of the squeeze number and Nusselt number is an increasing function of Hartmann number.

Enhanced Electroactive Phases of Poly(vinylidene Fluoride) Fibers for Tissue Engineering Applications.

Nanofibrous materials generated through electrospinning have gained significant attention in tissue regeneration, particularly in the domain of bone reconstruction. There is high interest in designing a material resembling bone tissue, and many scientists are trying to create materials applicable to bone tissue engineering with piezoelectricity similar to bone. One of the prospective candidates is highly piezoelectric poly(vinylidene fluoride) (PVDF), which was used for fibrous scaffold formation by electrospinning. In this study, we focused on the effect of PVDF molecular weight (180,000 g/mol and 530,000 g/mol) and process parameters, such as the rotational speed of the collector, applied voltage, and solution flow rate on the properties of the final scaffold. Fourier Transform Infrared Spectroscopy allows for determining the effect of molecular weight and processing parameters on the content of the electroactive phases. It can be concluded that the higher molecular weight of the PVDF and higher collector rotational speed increase nanofibers' diameter, electroactive phase content, and piezoelectric coefficient. Various electrospinning parameters showed changes in electroactive phase content with the maximum at the applied voltage of 22 kV and flow rate of 0.8 mL/h. Moreover, the cytocompatibility of the scaffolds was confirmed in the culture of human adipose-derived stromal cells with known potential for osteogenic differentiation. Based on the results obtained, it can be concluded that PVDF scaffolds may be taken into account as a tool in bone tissue engineering and are worth further investigation.

Solute flow and particle transport in aquatic ecosystems: A review on the effect of emergent and rigid vegetation

In-channel vegetation is ubiquitous in aquatic environments and plays a critical role in the fate and transport of solutes and particles in aquatic ecosystems. Recent studies have advanced our understanding of the role of vegetation in solute flow and particle transport in aquatic ecosystems. This review summarizes these papers and discusses the impacts of emergent and rigid vegetation on the surface flow, the advection and dispersion of solutes, suspended load transport, bedload transport, and hyporheic exchange. The two competing effects of emergent vegetation on the above transport processes are discussed. On the one hand, emergent vegetation reduces mean flow velocity at the same surface slope, which reduces mass transport. On the other hand, at the same mean flow velocity, vegetation generates turbulence, which enhances mass transport. Mechanistic understanding of these two competing effects and predictive equations derived from laboratory experiments are discussed. Predictive equations for the mean flow velocity and turbulent kinetic energy inside an emergent vegetation canopy are derived based on force and energy balance. The impacts of emergent vegetation on the advection-dispersion process, the suspended load and bedload transport, and the hyporheic exchange are summarized. The impacts of other vegetation-related factors, such as vegetation morphology, submergence, and flexibility, are briefly discussed. The role of vegetation in transporting other particles, such as micro- and macro-plastics, is also briefly discussed. Finally, suggestions for future research directions are proposed to advance the understanding of the dynamic interplays among natural vegetation, flow dynamics, and sedimentary processes.

How borehole wall elasticity affects wellbore storage capacity in periodic hydraulic tests

Characterizing fluid transport and pore pressure diffusion is key for monitoring and understanding many natural (e.g., seismically active zones and volcanic systems) and engineered environments (e.g., enhanced geothermal reservoirs and CO2 underground storage). Borehole hydraulic testing allows for inferring relevant properties of the probed subsurface volume, such as, for example, its transmissivity and diffusivity, assessing the governing flow regime as well as detecting the presence of hydraulic boundaries. Periodic hydraulic tests (PHT) achieve these objectives using an oscillatory fluid injection procedure while measuring the fluid pressure response in monitoring boreholes. The relevant information on the pressure diffusion process occurring in a probed formation is retrieved from the phase shifts and amplitude ratios between the flow rate and the interval pressure. In general, the interpretation of PHT data relies on the assumption that the pressure diffusion process is largely unaffected by the deformation of the probed rock volume. To assess this assumption, we present a conceptual PHT model based on the theory of poroelasticity to investigate the role played by hydromechanical coupling (HMC) effects during PHT and to assess whether and to what extent additional mechanical information can be extracted from these tests. These effects include the influence of the borehole wall deformation on the wellbore storage coefficient Sw, which quantifies the difference between the injected flow rates and those actually entering the porous formation. We show that, in homogeneous formations, the commonly taken approach based on the uncoupled diffusion solution for radial flow reproduces the results of our HMC model. However, neglecting the deformation effect of the borehole wall on the storage capacity of the system during injection can lead to underestimations of both transmissivity and diffusivity, particularly at shorter oscillation periods. We present analytical expressions for the borehole wall deformation contribution to Sw, which depends on the shear modulus and does not change with the oscillatory period. We show that it is possible to obtain the effective Sw along with the transmissivity and diffusivity using observations at various oscillatory periods. In the presence of hydraulic boundaries, such as no-flow or constant-pressure boundaries, at a given distance from the injection borehole, Sw becomes period-dependent, introducing apparent variations in the inferred shear modulus of the formation if the associated HMC effects are not accounted for. Our results thus highlight the importance of accounting for HMC effects in PHT data interpretation, not only to reliably and accurately characterize and monitor hydraulic properties but also to fully exploit the potential of PHT to provide additional information on the mechanical behaviour of the probed rock volume.

Effect of an inclined magnetic field on dispersion of solute in a pulsatile flow through a channel of absorptive porous walls

The present investigation gives an insight to comprehend the complex mechanism of species transport through porous walls, which has applications for crude oil refining, oil reservoir engineering, and separation of metal from fluids. The paper analyzes the impact of an inclined magnetic field on mass transport phenomena of solute through an unsteady, viscous, incompressible, and electrically conducting fluid flowing between two parallel plates. Both plates are permeable, and the flow is driven by a periodic pressure gradient. At both channel walls, the first order boundary reaction is applied. The governing time depending advection and diffusion equation is solved numerically based on Aris's method of moments. To determine the axial mean concentration distribution of solute, the first four central moments are used in a Hermite polynomial representation. It is significant to note that the dispersion of tracer is more significant for the low frequencies rather than the high frequencies. The behavior of the dispersion process of the tracer is studied for various flow parameters such as the angle of inclination of the magnetic field (α), Hartmann number (M), absorption parameter (β), suction Reynolds number (R), injection Reynolds number (R′), Womersley number (ω), and dispersion time (t) for both purely oscillatory and combined flows. It is significant to note that with the increment of R, α, and M, the amplitude of the dispersion coefficient of the solute reduces. On the other hand, an opposite phenomenon is observed for R′. It is seen that the transport coefficient moves cyclically with a double frequency period for all values of R and R′. Also, it is found that the peak of the mean concentration distribution enhances with the increment of α and M because the flow velocity decreases.