Suction Velocity Research Articles

Mixed convection of shear-thinning hybrid nanofluid flow across a radiative unsteady cone with suction and slip effect

The present study examines the intricate dynamics of flow velocities, temperature distribution, and concentration profiles within Casson hybrid nanofluids as they traverse an unsteady vertical rotating cone, accounting for suction velocity and slip effects. The investigation dissects shear stress rates and thermal and mass transfer rates, leveraging the computational power of MATLAB's bvp4c method to tackle the problem's high non-linearity. The research extends to explore the interplay of magnetic parameters, radiation parameters, thermophoresis, Brownian motion, and chemical reactions in the context of Casson hybrid nanofluid flow over an unsteady vertical rotating cone. The incorporation of velocity slip effects and suction velocity emerges as a pivotal catalyst, elevating the rates of heat and mass transfer. Notably, the findings reveal a substantial enhancement in tangential and azimuthal skin friction by 52 % and 34 %, respectively, when transitioning from Casson nanofluid to Casson hybrid nanofluid. Most strikingly, the rate of heat transfer experiences a remarkable surge of 125 % when Casson hybrid nanofluid supplants Casson nanofluid. This research opens up exciting possibilities for improving heat and mass transfer in various industrial applications, making it a compelling contribution to the field of fluid dynamics and nanofluid research.

ელექტროგამტარ სითხეში წრიული ფოროვანი ფირფიტის ბრუნვის სტაციონარული ამოცანა გაჟონვის სიჩქარის დიდი მნიშვნელობებისათვის თბოგადაცემით, მაგნიტური ველისა და ჯოულის სითბოს გათვალისწინებით

The stationary problem of rotation of a circular porous plate in an electrically conductive fluid is studied by the sequential approximation method (Green's function and small parameter method) for large values of the suction velocity with heat transfer, taking into account a weak magnetic field. The problem considers the case when the influence of dissipative members on heat transfer is very small, the energy equation takes into account the influence of Joule's heat on heat transfer, and it is assumed that the temperature along with the radius of the plate changes according to the square law. For solving the problem, the Navier-Stokes and energy partial differential equations of fluid motion in a magnetic field are reduced to ordinary nonlinear differential equations using generalized Karman embeddings, the solutions of which are sought in the form of infinite series for small values of the suction parameter. The solution of the problem by the means of Green's function is reduced to the solution of integral-differential equations. Recurrence formulas have been obtained, by the means of which it is possible to calculate the solution with any approximation. The first two approximations are clearly calculated. All kinematic characteristics of fluid flow are calculated. Images for heat transfer and pressure distribution on a circular plate are obtained. The moment of resistance to rotation of the plate and the heat transfer coefficient are also calculated.

A novel anti-hydropressure piezoelectric jetting micro thruster for steering AUV

Achieving agile steering motion without auxiliary forward velocity is difficult for autonomous underwater vehicle (AUV) driven by rudders. Although installing vectored thrusters and more propellers can adjust AUV's posture in situ, the system complexity, cost and volume are multiplied due to the assembled sealing and anti-pressure devices. It is inaccessible to operate in deep-sea unstructured regions. Hence, a novel micro 3.2 cm-diameter piezoelectric jet thruster suitable for high-pressure environment is proposed, which realizes dual-drive system integration without increment in volume and structure complexity after a simple gluing insulation. The high-frequency micron-level deformation of piezoelectric vibrator directly acts on the cavity to form a m/s-level jet with no transmission structure. To achieve high-efficient propulsion of the thruster, the vibration characteristic of vibrator, the flow field and pressure variation and the driving enhancement mechanism are numerically investigated. Then, the exciting waveform parameters, the cavity and nozzle shapes are optimized, and the corresponding fluid flowing state behind is analyzed. The findings indicate that the opposite positions of maximum suction and ejection velocities, and their final values synergistically dominate driving force improving. And the largest average driving force occurs in the thruster with contractive hyperbolic-shaped cavity and nozzle. Reducing the suction velocity and time by changing the duty ratio and falling edge of the square wave is incapable of enhancing the driving performance. In addition, the consistent motion velocity without attenuation below 20 MPa water pressure proves the propulsion feasibility in deep sea. The AUV with body length (BL) of 32 cm can achieve agile steering motion directly driven by the integrated thruster without influencing the original streamlined structure, and the needed steering radius is only 0.42 times as long as its length. This work presents an effective solution for maneuvering deep-sea underwater vehicle in the narrow regions such as the seabed slit and gully.

A Simple, Cost-effective Microsuction Device.

In our proposed device, we converted a large suction tube into a small tube with reduced suction velocity. This can aid in microsurgical procedures in which meticulous suctioning while minimizing trauma to the surrounding structures is essential. This device can relieve the surgeon from having to be cautious about injuring any anastomoses or neurovascular structures while suctioning.

Influence of an induced magnetic field and flow behavior of (AA7072–AA7075/water) hybrid nanoliquid in a vertical channel with suction velocity

Influence of an induced magnetic field and flow behavior of (AA7072–AA7075/water) hybrid nanoliquid in a vertical channel with suction velocity

Effect of radiation absorption and chemical reaction on MHD‐free convective flow through a porous medium past an infinite vertical porous plate in the presence of constant heat flux

AbstractAn incompressible, electrically conducting, and viscous fluid flowing steadily and freely across a uniformly porous media that is partially constrained by an infinitely long vertical porous plate is studied in the present article. Additionally, chemical reaction and radiation absorption effects are seen. Here, a magnetic field of uniform strength is applied transversely to the plate, a normal suction velocity is imposed on the fluid, and the heat flux is considered to be constant. The non‐dimensional momentum and energy equations are solved using the method of perturbation. The problem has been analytically resolved, and several parameters, including the Hartmann number, porosity parameter, thermal Grashof number, mass Grashof number, and transport properties like the Sherwood number, skin friction, and plate temperature, are graphically represented. The current study reveals a spike in the radiation absorption effect causes skin friction to drop, but on the other hand, a contrary effect is observed for plate temperature. One of the notable findings of this investigation is that the Sherwood number increases as chemical reaction parameter influence increases.

Unsteady MHD hybrid nanofluid flow over a convectively heated linear stretching cylinder with velocity slip: A comparative study

This paper provides a comparative numerical analysis of unsteady hybrid nanofluid ([Formula: see text]/H2O) and nanofluid (TiO2/H2O) flows through a permeable linear stretching cylinder placed in a porous medium has been presented in the presence of oblique Lorentz force. The flow regulating boundary layer equations has been governed due to the sway of the suction, viscous-Ohmic dissipation, heat source, thermal radiation and first-order velocity slip with imposing convective boundary conditions on the surface. The self-similar transformation has been employed to convert the governing coupled nonlinear PDEs into a set of ODEs and finally solved them numerically by fifth-order Runge–Kutta method with shooting technique. Finally, a comparative study has been made on the thickness of the momentum and thermal boundary layers due to the effect of governing parameters for simple and hybrid nanofluids. Further, a numerical observation on local skin friction and thermal-transport coefficients is presented with the help of tables. The result indicates that the progressiveness of the velocity profile reduces for the unsteadiness parameter, Hartree pressure gradient, velocity slip parameter, inclination parameter, porous medium parameter, magnetic parameter and suction parameter while improving for velocity ratio parameter and temperature profiles increases with Biot number, Eckert number, heat generation parameter and thermal radiation parameter, but decreases for Hartree pressure gradient and velocity ratio parameter. This work has found various applications in high-temperature and cooling processes, paints, conductive coatings, medicines, space technology, biosensors, conductive coatings and so on.

SORET AND DUFOUR EFFECTS IN A THREE-DIMENSIONAL MHD FLOW PAST A SEMI-INFINITE UNIFORMLY MOVING VERTICAL PLATE WITH CONSTANT HEAT FLUX

In this paper, we have considered the three-dimensional MHD flow past a semi-infinite uniformly moving porous plate with Soret and Dufour effects. The plate is subjected to a sinu-soidal suction velocity and constant heat flux. It is assumed that a uniform magnetic field is applied normal to the plate and directed into the fluid region. But the induced magnetic field is neglected in the study on the assumption that the magnetic Reynolds number is very small. The analytic solutions are obtained by adopting the method of perturbation technique. The influence of magnetic field parameter, thermal diffusion and diffusion-thermo effects on the flow, heat and mass transfer characteristics are mainly focused on the study. It is found from our study that fluid velocity increases under the influence of Soret and Dufour effects.

A suction method to mitigate pressure waves induced by high-speed maglev trains passing through tunnels

When a high-speed maglev train travels through a tunnel, sudden pressure changes are generated in the tunnel, which have a negative impact on the comfort of passengers and the service life of equipment. Moreover, a strong micro-pressure wave is radiated, causing environmental noise at the tunnel exit. Using the unsteady compressible Reynolds-averaged Navier–Stokes equations based on the shear stress transport k-ω turbulence model, this study investigates the effectiveness of suction (deployed on the tunnel wall) to mitigate the pressure waves and compares the results obtained under different suction velocities. The results show that when the suction is actuated, a low-pressure region is generated near the suction slots, which can trim down the initial compression wave and the high-pressure region in front of the train. Moreover, the instantaneous train surface pressure, tunnel surface pressure and micro-pressure wave have a significant relationship with the suction velocity. For instance, compared to the no suction case, the suction-actuated case with the suction velocity of 50 m/s contributes to an amplitude reduction of 10.44% and 30.61% for the first and second sudden pressure changes, respectively, at train surface measuring point H1 (at the nose of the train); an amplitude reduction of more than 14% for the sudden pressure change at tunnel surface measuring point T17 (at the middle of the tunnel); and an amplitude reduction of 12.44% for the micro-pressure wave at measuring point M2 (outside the tunnel and 20 m from the tunnel exit). These indicate that the suction technique can be employed to alleviate the tunnel aerodynamic effect. Also, the results obtained under different suction velocities can serve as a guide for the design of suction actuators.

Validation of Suction Velocity Analysis for Active Laminar Flow Control with Uncertainties

This study provides a validation of a recently developed uncertainty quantification methodology for suction velocities with the example of a novel laminar flow control design referred to as a tailored skin single duct (TSSD) panel. The TSSD panel is located on the leading edge of a vertical fin model of an Airbus A320 that is designed to maintain and extend laminar flow over the fin by means of boundary-layer suction. The suction velocities are highly dependent on the local porosity, which is only partly known in practice; therefore, the associated uncertainties need to be quantified. This is achieved by combining experimental and numerical data. The experimental data are based on the wind-tunnel experiments on a full-scale Airbus A320 vertical fin equipped with the TSSD system performed in the large low-speed facility of the German–Dutch Wind Tunnels. The measurements also feature highly accurate mass flow measurements of the integral mass flow through the TSSD system that serve as a validation reference for the uncertainty analysis. Uncertainties are provided for the predicted and the measured total mass flows to validate the proposed method, and a good agreement is obtained. A sensitivity study reveals the most influential contributions to the variance of the computed suction velocities. Depending on the difference between plenum and outer pressure, either uncertainties in the pressure distribution or uncertainties in the porosity parameters dominate the variance of the suction velocity.

Study on Flow Characteristics of Hydraulic Suction of Seabed Ore Particles

Efficient and environmentally friendly ore collecting operation requires that the ore collecting head can provide just enough suction to start the ore particles in different working conditions. In this work, computational fluid dynamics and discrete element method (CFD-DEM) is used to simulate the hydraulic suction process of ore particles. After analyzing the pressure and velocity characteristics of the flow field, the effects of different suction velocities on the lateral displacement offset, drag coefficient Cd and Reynolds number Rep of particles are studied. It is determined that the lifting force is caused by the different flow velocities of the upper and lower flow fields; particle start-up time and the lateral offset are inversely proportional to suction speed. When h/d ≥ 2.25, the vertical force on particles is no longer affected by h/d. When S/d = 2.5, FZ decreases to 0 N; when h/d increases from 1.5 to 1.75, FZ decreases by nearly half. Three empirical equations for FZ represented by D/d, h/d, and S/d are obtained. After integrating the above three equations, the functional relationship of FZ with D/d, h/d and S/d is finally obtained within a certain range. The errors of the equations are within 6%. The particle stress characteristics obtained in this paper can be applied to the establishment of ore collecting performance prediction model and provide data support for the research and development of intelligent ore collecting equipment.

EFFECT OF INTERNAL HEAT AND VARIABLE ELECTRICAL CONDUCTIVITY ON CONVECTIVE MHD FLOW ALONG A VERTICAL ISOTHERMAL PLATE

The study investigates convective MHD flow of incompressible fluid of low Prandtl number along a vertical non-conducting plate in porous medium at constant temperature where fluid is sucked through a vertical plate with a constant suction velocity under the action of small internal volumetric heat generation and transverse magnetic field applied externally. The electrical conductivity of the fluid is considered to be temperature dependent variable. Incorporating the Boussinesqs approximation for the boundary layer flow and considering the action of local specific dissipation of mechanical energy due to permeability of the medium, numerical values of various flow parameters such as velocity, temperature, skin-friction, heat transfer etc. are calculated numerically, analysed graphically and conclusions are drawn.

A pathway for multi-stage cyclone-induced hazard tracking—case study for Yaas

A Very Severe Cyclonic Storm ‘Yaas’ developed over the Bay of Bengal (BoB) on 23 May 2021 and crossed over the Odisha coast on 26 May with maximum sustained wind speed of 75 kts. Herein, a pathway has been developed and exemplified for ‘Yaas’ through three-stage cyclone-induced hazard tracking. Days before the cyclone formation, cyclone genesis potential parameter, sea surface temperature (SST) (> 30 °C) and tropical cyclone heat potential (anomaly of 40–80 kJ/cm2) indicated a strong possibility of cyclogenesis in the BoB. A Lagrangian advection model used for its track prediction with 24-h lead-time provided an accuracy of ~ 19 km and ~ 6 h in its landfall location and time. Further, intensity prediction was done using numerical weather prediction model. Geostationary satellites, INSAT-3D/3DR, were used to visualize cyclone structure. Passing of cyclone had its reverbarations in oceans, which are observed in SST drop of ~ 3 °C, salinity and density increase by ~ 1 psu and ~ 2 kg/m3, respectively. During the period, 23–26 May 2021, the Ekman suction velocity and chlorophyll concentration were found significantly high at ~ 5 m/day and > 0.5 mg/m3, respectively. Forecast of storm surge was found to be between 3.5 and 4 m at coastal locations. Significant wave height was found to be 5.5–9.2 m. The coastal inundation forecast for 24 May 2021 provided its quantitative maximum inland extent. Finally, loss of the crop, fishery and forest areas by strong winds and inundation/ingress of saline water associated with storm surge were examined using SAR and optical data.

Heat transfer analysis of the MHD stagnation-point flow of third-grade fluid over a porous sheet with thermal radiation effect: An algorithmic approach

Abstract The present article aims to investigate the impacts of the thermal radiation and Lorentz force on the stagnation-point flow of third-grade liquid over a porous stretching sheet with suction. The governing equations are transformed using the similarity transformation. The resulting system of ordinary differential equations is solved using a “so-called” hybrid algorithm based on the finite difference method and the shooting method. The influence of the emerging parameters on the velocity and temperature profiles is analyzed. The results are shown in graphical and tabular forms. For the third-grade liquid flow, the velocity profile shows an inciting trend toward the Hartman number (magnetic parameter). The temperature profile shows a declining trend toward the Prandtl number and suction velocity, whereas an inciting trend towards the radiation parameter.

Diffusion Thermo and Chemical Reaction Effects on Magnetohydrodynamic Jeffrey Nanofluid Over an Inclined Vertical Plate in the Presence of Radiation Absorption and Constant Heat Source

This article investigates the Diffusion thermo and chemical reaction effects on the free convection heat and mass transfer flow of Jeffrey nanofluids (Cu and TiO2) over an inclined porous vertical plate embedded in a porous medium in the presence of radiation absorption and constant heat source under fluctuating boundary conditions. The plate is moved with a constant velocity U0, temperature and the concentration are assumed to be fluctuating with time harmonically from a constant mean at the plate. Perturbation technique is applied to solve the governing equations of the flow and pointed out the variations in velocity, temperature and concentration with the use of graphical presentations. The impact of several parameters on local skin friction, Nusselt number and Sherwood number is also noticed and discussed. It is concluded that the resultant velocity reduces with increasing Jeffrey parameter and Suction parameter, velocity and Temperature enhances with increasing Radiation absorption parameter. Also it is noticed that the solutal boundary layer thickness decreases with an increase in chemical reaction parameter. It is because chemical molecular diffusivity reduces for higher values of Kr.

Magnetohydrodynamic hybrid nanofluid flow over a decelerating rotating disk with Soret and Dufour effects

PurposeThe investigation of fluid flow over a rotating disk has been increasing due to the spread of machine technology. Because of this development, we scrutinized the Magnetohydrodynamic (MHD) flow of hybrid nanofluid caused by a decelerating rotating disk with Ohmic heating, Soret and Dufour effects. The disk's angular velocity is taken to be an inversely time-dependent linear function. Moreover, the temperature-dependent viscosity of hybrid nanofluid is incorporated in the present investigation. Methanol is considered as base fluid, while copper oxide (CuO) and magnesium oxide (MgO) are nanoparticles.Design/methodology/approachEstimated fundamental partial differential equations of flow problems are altered as a dimensionless system of ordinary differential equations using appropriate similarity transformation and solved using a numerical technique: BVP Midrich scheme in Maple software. The impression of emerging non-dimensional parameters is portrayed graphically. All outcomes are shown in the velocity, temperature and concentration profiles.FindingsThe developed flow problem involves a non-dimensional parameter (A) that reveals the deceleration of the disk. For larger values of A, the disk decelerates faster and for some fixed time, the fluid surrounding the disk revolves more rapidly than the disk itself. The radial velocity of fluid diminishes and axial velocity becomes uniform when the disk is subjected to wall suction velocity (B).Originality/valueThis analysis is significant in biomedical engineering, cancer therapeutic, manufacturing industries and nano-drug suspension in pharmaceuticals. The novelty of the current study is the hybrid nanofluid flow with Ohmic heating, Soret and Dufour effects on a decelerating rotating disk. To the best of the author's knowledge, no such consideration has been published in the literature.

NATURAL CONVECTIVE MHD MASS TRANSFER FLOW PAST AN INFINITE VERTICAL POROUS PLATE EMBEDDED IN A POROUS MEDIUM WITH THERMAL DIFFUSION AND CHEMICAL REACTION

The intent of this current exploration is to examine the natural convective magnetohydrodynamics (MHD) mass transfer flow past an infinite vertical porous plate implanted in a porous medium with thermal diffusion and chemical reaction. An analytical solution for momentum, energy, and concentration equations is achieved by implementing the perturbation method. A uniform magnetic field is installed orthogonally with the plate and the fluid undergoes a normal suction velocity with the consideration that heat flux at the plate is constant. In contemplation of recording the influence of different nondimensional parameters and deliberating the flow characteristics, the computational aftermath for fluid velocity, temperature, and species concentration is portrayed graphically. Investigations divulge the fact that the increase in thermal diffusivity causes hefty falls in the temperature field and improves the concentration of the fluid. Again it is also noted that the fluid velocity and species concentration dwindle as a result of a high rate of consumption of species. The solutions obtained in this study are attained asymptotically.

Double-diffusive convection in viscous flow over a rotating porous and moving disk

This paper presents the double-diffusive convection in the flow of viscous fluid over a heated, rotating, porous and moving disk. All the field quantities, defined at the surface of such disk, are nonuniform and nonlinear, therefore, the boundary conditions of the simulated problem are nonhomogeneous and variable. A set of new variables is found and it has simplified the system of six PDE's along with the boundary conditions into a system of coupled ODE's of boundary value type. The system of nonlinear, coupled and boundary value ODE's has some nine dimensionless parameters, whereas, effects of these numbers have been seen on all field variables, tangential and surface shear stresses and rates of heat and mass transfer. The present simulations have generalized the concept of rotating disk flows in the sense that the three components of velocity, associated with the disk, are taken nonuniform and nonlinear, whereas, the other thermodynamic properties, specified at the surface of the disk, also have the nonlinear nature. In this investigation, we focused on weak and strong assisting and opposing flows of liquids and gases over a rotating disk in the presence of stretching, shrinking, injection and suction velocities. Each component of velocity is effectively (slightly) enhanced with the variation of and in case of assisting (opposing) flow in the presence of stretching/shrinking and injection/suction. Moreover, similar behavior of the other field variables and quantities of physical interests has been noticed. Thin momentum, thermal and concentration boundary layers are appeared in some cases, which are clearly demonstrated in graphs in special situations.

Time-dependent flow of water-based ternary hybrid nanoparticles over a radially contracting/expanding and rotating permeable stretching sphere

• The stream of ternary hybrid nanoliquid on a flexible shell of a solid sphere, water-based TiO2, GO and Ag nanoparticles are all employed to study the flow variation. • Study inspects the flow produced by spinning, suction-driven, radially shrinking or expanding stretching sphere. • A detailed explanation of a solution procedure for accommodating non-similar momentum boundary layers is discussed. • The external validation criteria are employed to address the modeling overfitting. This work concentrates on the flow of ternary nanofluid flow over a rotating sphere in view of cooling of rotating spherical products in various industries, machinery fields, and other applications. Here, considered nanoparticles have various practical applications for cooling in various industrial processes. This study is considered innovative because it examines the effect of three different nanoparticles on the flow over a rotating sphere with expansion/contraction reported for the first time. Ternary-hybrid nanofluid is a comprehensive combination of a fluid material with three different types of nano-sized particles. Recent findings concerning the potential and applications of nanofluids have revealed several facts about the nature of nanoparticles and their ability to influence the rate of heat transmission across the base fluid. Considering the aforementioned cause, the objective of this work is to explore the flow produced by spinning, suction-driven, radially shrinking or expanding stretching sphere. Initially, the problem is bounded in the requisite posited form of PDEs which are non-linear and coupled. A details description of a solution procedure for accommodating non-similar momentum boundary layers is also discussed. The terms (non-similar) that make up the obtained converted equations are maintained without approximations. Moreover, these non-similarities set of equations is tackled numerically via the help of bvp4c. Several graphs and tables are equipped for the influence of sundry controlling parameters. It is discovered that in circumstances of contracting, expanding and non-growing wall deformation, the region (equatorial) is efficiently smoothed out by the wall mass transpiration. When the sphere expands, the radial inward flow at the equator is no longer relevant and intense suction results in virtually constant radial suction velocities. Finally, the grid sensitivity analysis test is also performed for the ternary hybrid nanoparticles to show that the outcomes are asymptotically converged.

Evolution of hydrogen bubbles at the surface of a porous horizontal cathode

A simple model of hydrogen evolution at a horizontal cathode at the bottom of an acidic aqueous solution is proposed. The model accounts for convection due to suction of liquid through the electrode, as well as diffusion and migration of the charged species. The rate of growth of hydrogen bubbles and their spacing on the electrode are computed as functions of the mean current density and the suction velocity.