Slanted Surface Research Articles

Stacking regression model approach to mixed convection flow of ternary- nanofluid over slanted surface with magnetic field, waste discharge concentration, and joule heating effects

The current work is carried out to investigate the mixed convection flow behavior of ternary-based nanofluid over an inclined surface in the presence of a magnetic field, waste discharge concentration, and joule heating effects. The governing equations with proper assumptions were converted into ordinary differential equations (ODEs) form by implementing suitable similarity constraints and solved with Runge Kutta Fehlberg 4th 5th order and shooting scheme. The stacking regression model approach is implemented along with the Runge Kutta Fehlberg 4th 5th order technique. The obtained outcomes are presented with graphs, and model correctness is assessed using the combination of Gaussian Process Regression (GPR), Extra Tree Regression (ETR), and Random Forest (RF). The consistency and stability of the model are demonstrated by the closely linked testing and training data. The study outcomes show that the rise in the magnetic constraint will improve the velocity profile while improved values of local pollutant external source and external pollutant source variation parameters will enhance the concentration profile. Enhancement in Eckart number and solid volume fraction values will improve the rate of thermal distribution. Ternary nanofluid shows significant improvement than nanofluid. The surface drag force is increased about 8 %-9 % in assisting flow case and 8 %-17 % for opposing flow case for different values of magnetic parameter, the rate of thermal distribution improved from 75.54 % to 11.55 % in assisting flow case and 16.87 % to 25.70 % in opposing flow case for different values of Eckert number. The study's results might contribute to the advancement of more effective heat exchangers and cooling systems for electronics and engines. Exploration and extraction of oil, as well as the creation of efficient water purification systems.

A Wearable Haptic Device for the Hand With Interchangeable End-Effectors.

This article presents a 4-degrees-of-freedom (4-DoF) hand wearable haptic device for Virtual Reality (VR). It is designed to support different end-effectors, that can be easily exchanged so as to provide a wide range of haptic sensations. The device is composed of a static upper body, secured to the back of the hand, and the (changeable) end-effector, placed in contact with the palm. The two parts of the device are connected by two articulated arms, actuated by four servo motors housed on the upper body and along the arms. The article summarizes the design and kinematics of the wearable haptic device and presents a position control scheme able to actuate a broad range of end-effectors. As a proof of concept, we present and evaluate three representative end-effectors during interactions in VR, rendering the sensation of interacting (E1) with rigid slanted surfaces and sharp edges having different orientations, (E2) with curved surfaces having different curvatures, and (E3) with soft surfaces having different stiffness characteristics. A few additional end-effector designs are discussed. A human-subjects evaluation in immersive VR shows the broad applicability of the device, able to render rich interactions with a diverse set of virtual objects.

A 4-DoF wearable hand device for haptic rendering of surfaces and edges

We present a 4-degrees-of-freedom (4-DoF) wearable haptic device for the palm, able to provide the sensation of interacting with slanted surfaces and edges. It is composed of a static upper body, secured to the back of the hand, and a mobile end-effector, placed in contact with the palm. They are connected by two articulated arms, actuated by four servo motors housed on the upper body and along the arms. The end-effector is a foldable flat surface that can make/break contact with the palm to provide pressure feedback, move sideways to provide skin stretch and tangential motion feedback, and fold to elicit the sensation of interacting with different curvatures. The paper presents the design of the wearable haptic device, together with its mobility, statics, and manipulability, as well as direct, inverse, and differential kinematics. We also present a position control scheme for the device, which is then quantitatively evaluated.

Exploring slip effects of ferrofluid film flow over a slanted rough surface

We examined the influences of slip parameters on the velocity and thermal characteristics of a ferrofluid film of fixed thickness. The flow is generated on a rough and inclined whirling surface that is positioned in an external magnetic (dipole) field. The similarity transformation reduces the model equations (continuity, momentum, energy and concentration), and the solution of the normalized coupled ordinary differential equations is carried out through the finite element process. The influences of slip effects, Brownian motion, thermophoresis and a heat source on the velocity (radial, tangential and axial), gravity (drainage, induced), temperature profile and concentration profile are determined. The tangential flow and temperature are both decreased by an increase in the velocity slip parameter, whereas drainage, induced, radial and axial flows are increased. Enlarging the thermal slip parameter decreases the temperature. Improving slip parameters (velocity and thermal) also improves the concentration profile. Both Nusselt and Sherwood numbers are found to improve on improving the velocity slip parameter, while they decrease on decreasing the thermal slip parameter. The results and insights from this work could be applied to a wide range of medicinal fields, such as targeted medication therapy and delivery, tissue engineering, etc. as well as different industrial processes including coating, lubrication, heat transfer, etc.

Numerical Analysis on Stagnation Point Flow of Micropolar Nanofluid with Thermal Radiations over an Exponentially Stretching Surface

Several industrial developments such as polymer extrusion in metal spinning and continuous metal casting include energy transmission and flow over a stretchy surface. In this paper, the stagnation point flow of micropolar nanofluid over a slanted surface is presenting also considering the influence of thermal radiations. Buongiorno’s nanoliquid model is deployed to recover the thermophoretic effects. By using similarity transformations, the governing boundary layer equations are transformed into ordinary differential equations. The Keller-box approach is used to solve transformed equations numerically. The numerical outcomes are presented in tabular and graphical form. A comparison of the outcomes attained with previously published results is done after providing the entire formulation of the Keller-Box approach for the flow problem under consideration. It has been found that the reduced sherwood number grows for increasing values of radiation parameter while, reduced Nusselt number and skin friction coefficient decreases. Furthermore, the skin-friction coefficient increases as the inclination factor increases, but Nusselt and Sherwood's numbers decline.

A numerical investigation on forced convection heat and mass transfer performance in a right triangular cavity

The objective of this numerical study is to examine how different Reynolds numbers impact heat and mass transfer in an unsteady forced convective two-dimensional flow within a right-angle triangular cavity. The lowest surface of the enclosure is held at a fixed temperature and concentration, whereas the slanted surface is taken to be a cool surface. Furthermore, the cavity's left wall is adiabatically positioned to move in two directions: upwards (aiding flow) and downwards (opposing flow), with a constant speed being maintained. The partial differential equations that govern the system are converted into a non-dimensional form through a straightforward transformation. The finite-element scheme is employed to solve these dimensionless equations. The analysis facilitates the investigation of the belongings of the Reynolds number on the heat and mass transfer appearances by using streamlines, isotherms, and isoconcentration lines. It is initiated that the temperature spreading as well as concentration within the cavity depends strongly on the Reynolds number. Moreover, the motion of the moving wall influences the patterns of fluid flow, temperature, and concentration fields. This study provides a comprehensive investigation into heat and mass transfer behavior occurring within a lid-driven right-angled triangular cavity moving in two opposite directions for aiding flow and opposing flow respectively.

Visual influence on bimanual haptic slant adaptation.

Adapting to particular features of a haptic shape, for example, the slant of a surface, affects how a subsequently touched shape is perceived (aftereffect). Previous studies showed that this adaptation is largely based on our proprioceptive sense of hand posture, yet the influence of vision on haptic shape adaptation has been relatively unexplored. Here, using a slant-adaptation paradigm, we investigated whether visual information affects haptic adaptation and, if so, how. To this end, we varied the available visual cues during the adaptation period. This process ranged from providing visual information only about the slant of the surface, or the reference frame in which it is presented, to only providing visual information about the location of the fingertips. Additionally, we tested several combinations of these visual cues. We show that, as soon as the visual information can be used as a spatial reference to link the own fingertip position to the surface slant, haptic adaptation is very much reduced. This result means that, under these viewing conditions, vision dominates touch and is one reason why we do not easily adapt to haptic shape in our daily life, because we usually have visual information about both hand and object available simultaneously.

Preliminary design of the FCC-ee vacuum chamber absorbers

In the FCC-ee study, it is proposed that electron and positron beams circulate at high current and high energy in a 92-km circumference twin ring. The present operational scenario foresees a first running step at an energy of 45.6 GeV and around 1.4 A current, which would generate copious amounts of synchrotron radiation (SR) power and flux. To guarantee a quick decrease of the photon desorption yields and so a fast vacuum conditioning, it has been proposed to use localized SR absorbers along the vacuum chamber, spaced about 5 m apart. This would also help contain the high-energy Compton-scattered secondaries once the beam energy is increased up to 182.5 GeV, later in the experimental program. In the preliminary design of FCC-ee vacuum chamber absorbers presented in this work, the SR thermal power is intercepted along around 100 mm of slanted surface. The temperature distribution in the adsorbers is estimated by Finite Element Analysis (FEA) and needs to be assessed to avoid any liquid-gas phase change within the water-cooling circuit. The cooling channels contain a twisted tape that increases the turbulence of water. This results in the desired heat transfer coefficient. The mechanical deformations due to the non-uniform temperature map are presented and analysed as well.

On Human-like Biases in Convolutional Neural Networks for the Perception of Slant from Texture

Depth estimation is fundamental to 3D perception, and humans are known to have biased estimates of depth. This study investigates whether convolutional neural networks (CNNs) can be biased when predicting the sign of curvature and depth of surfaces of textured surfaces under different viewing conditions (field of view) and surface parameters (slant and texture irregularity). This hypothesis is drawn from the idea that texture gradients described by local neighborhoods—a cue identified in human vision literature—are also representable within convolutional neural networks. To this end, we trained both unsupervised and supervised CNN models on the renderings of slanted surfaces with random Polka dot patterns and analyzed their internal latent representations. The results show that the unsupervised models have similar prediction biases as humans across all experiments, while supervised CNN models do not exhibit similar biases. The latent spaces of the unsupervised models can be linearly separated into axes representing field of view and optical slant. For supervised models, this ability varies substantially with model architecture and the kind of supervision (continuous slant vs. sign of slant). Even though this study says nothing of any shared mechanism, these findings suggest that unsupervised CNN models can share similar predictions to the human visual system. Code: github.com/brownvc/Slant-CNN-Biases.

On the unsteady interactions between a sweeping jet and afterbody vortices

In this paper, a sweeping jet was applied to control the afterbody vortices behind a 30° slanted-base cylinder at a Reynolds number of 87 000. Phase-locked stereo particle image velocimetry measurements were conducted during a sweeping jet actuation cycle, and insights of the complex three-dimensional interaction process between the sweeping jet and the afterbody vortices have been obtained for the first time. It is found that in the near-field of the jet orifice (x/c < 0.3), the jet swings from side to side over the endplate between the afterbody vortex pair. An intersection between them around x/c = 0.3 causes the sweeping jet to take on a zigzag pattern as it propagates downstream along the slanted surface. From x/c = 0.6 onwards, the intensity of this interaction decreases as the afterbody vortices become detached from the base. Nevertheless, the sweeping jet continues invading the afterbody vortices from their inner side and pushes its way outwards from the underside of the afterbody vortices causing them to weaken further. Furthermore, the interaction between sweeping jets and afterbody vortices results in a cyclic variation in the circulation of afterbody vortices, which increases in magnitude at downstream locations. Except for the phases where a merger between the afterbody vortex and the sweeping occurs, a reduction in the circulation is observed. Finally, the level of interaction between sweeping jets and afterbody vortices intensifies as the strength of the sweeping jet increases resulting in the afterbody vortices being penetrated by the sweeping jet and their regular shape being momentarily destroyed.

Detection of surface cracks on slanted surfaces and through thick irregular insulation layers using polarimetric microwave imaging

Reliable detection of cracks on slanted metal surfaces and through irregular insulation/coating is critical in many inspection applications. Microwave non-destructive testing (NDT) techniques have proven to be effective for crack detection and characterization. However, the utility of conventional microwave NDT techniques for challenging inspection scenarios which involve cracks on slanted surfaces, or cracks under relatively thick, and possibly, irregular insulation has been limited. In this paper, a polarimetric microwave imaging approach is employed for the detection of cracks in such inspection cases. The detection concept using interrogation with dual polarized wave to suppress the background is presented. It is established herein that the cross-polarization measurement is independent to irregular surfaces, and therefore, it constitutes an effective mean for reliable crack detection even if the background is not uniform or if the metal surface is slanted. This fact is further corroborated by numerical electromagnetic simulations and measurements. The efficacy of the proposed method is demonstrated using imaging results of various samples spanning the abovementioned scenarios.

Impact on Casson Nanofluid Flow Across an Inclined, Slanted Surface by Radiation, Energy and Mass Transfer

Casson nanofluid flow across a porous, slanted surface is investigated. In addition to the impact of a heat source, thermal energy, and a chemical reaction also are considered. Applying similarity transformations, the controlling nonlinear PDEs are converted to ODEs. To resolve the ordinary differential equations (ODEs), we used the universal numerical differential equation solver Wolfram Language function NDSolve. The distributions under heat source are affected by chemical processes and other variables are explored. While liquid velocity reduced due to inclination and the Casson factor, mass and energy transit rates rose. The findings are represented graphically and are consistent with past research. The findings would provide valuable insights into the flow patterns, temperature distribution, and concentration profiles within the system. This information can be crucial for designing and optimizing heat transfer systems, energy-efficient processes, and catalytic reactors involving Casson nanofluids and porous media.

A numerical model for predicting waves run-up on coastal areas

ABSTRACT In this study, numerical investigations are performed to validate a numerical model for the prediction of waves propagation and waves run-up on coastal zones. The proposed numerical model is based on the depth-averaged two-dimensional dispersive shallow water equations with source terms due to variable bottom topography and bed friction effects. We propose to solve the resulting nonlinear system using a well-balanced positivity preserving Godunov-type finite volume method on unstructured triangular grids. We used a semi-implicit scheme for the friction terms and a well-balanced formulation for the bottom topography. Moreover, we prove that the numerical scheme exactly preserves a class of nontrivial steady-state solutions. To validate the proposed numerical model against experiments, we first demonstrate its ability to preserve nontrivial steady-state solutions over a slanted surface and then we model several laboratory experiments for the prediction of waves run-up on sloping beaches. The numerical simulations are in good agreement with laboratory experiments which confirms the robustness and accuracy of the proposed numerical model in predicting waves propagation on coastal areas.

Vibration-induced crack tip flipping: A closer look at an unfamiliar phenomenon in pipeline failure analysis

Fracture propagation control is an essential strategy to avoid a catastrophic event involving both economic losses and environmental damage. The Dynamic Tensile Tear Test (DT3) was introduced as an alternative tool to characterise dynamic fracture behaviour of high-strength pipeline steels. Mimicking the in-service loading conditions by imposing a dynamic tensile load, the obtained fracture surfaces closely resemble those observed in full-scale pipeline burst tests. A phenomenon called Crack Tip Flipping (CTF) could also be observed in combination with the formation of Arrowhead Markings (AHMs). The mechanisms provoking these phenomena and their effect on the fracture resistance of the pipeline material have not yet been investigated with respect to pipeline failure. Therefore, a high-speed stereo DIC setup was used to study the fracture behaviour of ×70 grade pipeline steel. The DIC setup identified a mechanical out-of-plane vibration that resulted in an additional torsional loading component. Numerical models were constructed with implementation of the Modified Bai-Wierzbicki (MBW) damage model to validate the experimental observations. Imposing a vibration-induced out-of-plane component resulted in a nearly identical fracture behaviour as observed during experiments. Both the crack path and the final fracture surface could be reproduced. Based on the obtained data, it is suggested that this oscillation causes a rotation of the stress tensor controlled by the through-thickness shear component. As a result, the stress state at the crack front is oriented towards the plane of maximum shear, forming a slanted fracture surface. Notably, the additional torsion load did not affect the load-displacement curve, as the value of the effective stress remains unaffected. Consequently, the fracture resistance, computed from energy values extracted from the load-displacement curve, are not influenced by the occurrence of CTF or the formation of AHMs. Conversely, based on the discussed mechanism of CTF, its presence could indicate the conditions under which pipeline failure occurred.

Heat transport mechanism in glycerin-titania nanofluid over a permeable slanted surface by considering nanoparticles aggregation and Cattaneo Christov thermal flux.

The dynamics of superior heat transport fluids are of much interest and dominant over traditional fluids. Applications of such fluids can be found in advanced medical sciences, to maintain the building temperature, environmental sciences, chemical engineering, food engineering, and other applied research areas where enhanced heat transfer is required. The major aim of this research is to report the thermal performance of the Glycerin-titania nanofluid using a thermal conductivity model comprising the effects of nanoparticles aggregation, and CCTF over a permeable slanted surface. The enhanced heat transport model was then analyzed numerically via RK scheme and furnished the outcomes with graphical aid under the variations of physical parameters. It is examined that the addition of CCTF (A1) in the model potentially contributes to thermal performance of aggregated nanofluid. The temperature enhances for injecting fluid from the surface and reduces due to strong suction. Further, the fluid particles attained maximum velocity for at the surface and it shows asymptotic behavior far from the working domain.

Dissipative MHD free convective nanofluid flow past a vertical cone under radiative chemical reaction with mass flux

Recently, Nanoparticles have supplied diverse challenges to several scientific issues. Nanoparticles dispersed in a variety of conventional fluids can change the flow and heat transmission properties of the fluids. The mathematical technique is used in this work to investigate the MHD water-based nanofluid flow via an upright cone. The heat and mass flux pattern is used in this mathematical model to examine MHD, viscous dissipation, radiation, chemical reactions and suction/injection processes. The finite difference approach was used to find the solution to the basic governing equations. A combination of nanofluids comprising nanoparticles including aluminum oxide (Al_{2}O_{3}), silver (Ag), copper (Cu) and titanium dioxide (TiO_{2}) with a volume fraction of nanoparticles (0, 0.01, 0.02, 0.03, 0.04), viscous dissipation (epsilon = 0.4, 0.8), MHD (M = 0.5, 1.0), radiation (Rd = 0.4, 1.0, 2.0), chemical reaction (lambda = 0.2, 2.0) and heat source/sink (Delta = -3, -2 ,0.5 , 1) . The mathematical findings of velocity, temperature, concentration, skin friction, heat transfer rate as well as Sherwood number distributions are analyzed diagrammatically using non-dimensional flow parameters. It has been discovered that by increasing the value of the radiation parameter, velocity and temperature profiles enhance. The production of safe, high-quality products for consumers across the world depends on vertical cone mixers, from food to medicine, household cleansers to personal hygiene products. Every vertical cone mixer type we provide was especially developed to meet the demands of industry. As the mixer warms up on the slanted surface of the cone while vertical cone mixers are being utilized, the effectiveness of the grinding may be felt. The temperature is transferred along the cone’s slant surface as a consequence of the mixture being mixed quickly and repeatedly. This study describes the heat transmission in these events and their parametric properties. The heated cone’s temperature is then convective to its surroundings.

Effect of a Short, Bio-Mimetic Control Device on Aerodynamic Drag of Ahmed Body

Abstract The effects of short automatic moving deflectors (AMD) on the aerodynamic characteristics of Ahmed body are considered in this study. AMDs, known as biomimetic control devices, were added to the leading edge of the slanted surface. Its position was automatically adjusted in a separation flow. The aerodynamic drag, the pressure, and the skin-friction distribution on the slanted surface were measured for the model with three deflectors with lengths of 9%, 18%, and 30% of the slant. Particle image velocimetry was also utilized to assess the flow on the vertical symmetric plane. The Reynolds number based on the height of the model is between 1.44 × 105 and 2.80 × 105. The results showed that at a low Reynolds number, a short deflector increases the drag of the model. The effectiveness of the deflector in reducing the drag arises at a high velocity, where a maximum drag reduction of 11% was observed. The deflectors also reduced the lift coefficient by as much as 89%. Global luminescent oil-film skin-friction measurements showed that in the low drag state, the structure of the longitudinal vortexes and the separation bubble disappear on the surface. A complex flow structure is classified for the baseline model and the model with deflectors. The relationship between the surface flow, pressure distribution, and flow on the symmetric vertical plane is discussed in detail.

THE EFFECT OF THERMOPHYSICAL PROPERTIES ON NONLINEAR THERMAL-SOLUTAL CONVECTIVE FLOW OF CASSON NANOFLUID OVER AN INCLINED SURFACE WITH HIGHER ORDER CHEMICAL REACTION

The combined effect of Soret-Dufour, higher-order chemical reaction and variable thermophysical properties on nonlinear thermal and solutal convective flow of a non-Newtonian fluid (Casson nanofluid) over a slanted surface is analyzed. The nonlinear dimensionless equations governing the fluid flow are transformed into ordinary differential equations, using suitable similarity transformation variables. The flow fields and some characteristic numerical results are obtained from these equations, using collocation method with assumed Legendre functions of the first kind. These results are presented in the form of graphs and tables showing the impact of various parameters on the fluid flow, heat and mass characteristics. It is observed that a rise in chemical reaction parameter decreases the nanoparticle volume fraction while a higher order of chemical reaction makes it elevated. The velocity increases and temperature decreases with a rise in nonlinear thermal convection and higher value of nonlinear solutal convection has effect on the rise of velocity distribution.

E × B flow driven electron temperature bifurcation in a closed slot divertor with ion B × ∇B away from the X-point in the DIII-D tokamak

An electron temperature bifurcation is observed in the small angle slot divertor, which has been developed to enhance neutral cooling across the divertor target by coupling a closed slot structure with appropriate target shaping. Experiments in the DIII-D tokamak and associated SOLPS-ITER modeling with full drifts find a strong interplay between drifts and divertor geometry on divertor dissipation. The coupling of divertor geometry and drift flows can strongly affect the path towards divertor detachment onset as the plasma density is raised. With the strike point on the inner slanted surface and ion B × ∇B away from the magnetic X-point, bifurcative transitions were observed with sharp decrease of T e towards detachment onset both experimentally and computationally. This differs from the situation for the open divertor where the T e cliff was only observed for ion B × ∇B towards the X-point. SOLPS-ITER modeling with full drifts demonstrates that the magnitude of the E × B drift flow is comparable with the main plasma flow. The reversal of both the poloidal and radial E × B flows near the strike point leads to rapid density accumulation right near the separatrix, which results in bifurcative step transition of divertor conditions with cold plasma across the entire divertor target plate. These results indicate that the interplay between geometry and drifts should be fully taken into account in future fusion reactor divertor designs.

Dependence of particle and power dissipation on divertor geometry and plasma shaping in DIII-D small-angle-slot divertor

• The compact SAS divertor in DIII-D provides a good testbed for understanding the effects of a tightly closed divertor on particle and power dissipation, and for application to core-edge integration solutions. • A longer outer leg facilitates the achievement of divertor dissipation in the SAS divertor, while a shorter leg leads to higher divertor temperatures and requires higher upstream densities to achieve the same level of divertor detachment. • The divertor conditions strongly depend on the divertor target shaping and Bt direction. • In-slot gas puffing can reduce detachment onset density by about 10% when the outer strike point is placed at the inner slanted surface. • Completed divertor detachment and a high confinement core with normalized energy confinement factor H 98 >1.0 can be simultanesouly achieved with the SAS divertor, demonstrating the benefit of a closed divertor for exploration of core-edge integration. Dedicated experiments in DIII-D find that magnetic shaping and divertor target geometry significantly affect the divertor plasma conditions and divertor detachment process in the small-angle-slot (SAS) divertor. The compact SAS divertor in DIII-D provides a good testbed for understanding the effects of a tightly closed divertor on particle and power dissipation, and for application to core-edge integration solutions. A longer outer leg facilitates the achievement of divertor dissipation in the SAS divertor, while a shorter leg leads to higher electron temperatures near the divertor target plate and requires higher upstream densities to achieve the same level of divertor detachment. In addition, with the ion B × ∇ B drift away from the SAS divertor and the outer strike point (OSP) near the outer corner, the target temperature is lower for a particular upstream density than with the OSP on a slanted or flat surface, leading to lower heat flux even when the particle flux remains similar. In contrast, with the ion B × ∇ B drift into the SAS divertor, a strike point at the inner slanted surface exhibits a lower upstream density to achieve divertor detachment than a strike point either at the outer corner or the outer slanted target. Experimental results and SOLPS-ITER simulations with full drifts suggest the strong interplay between drift flows and the neutral distribution resulted from target shaping. Furthermore, in-slot gas puffing has been shown to achieve global divertor detachment with an onset density about 10% lower than that using main-chamber gas puffing when the outer strike point is placed at the inner slanted surface. Corresponding modelling reveals that the local gas puffing enhances the neutral ionization which potentially facilitates the achievement of divertor dissipation. However, such improvement diminishes when the strike point is at the outer corner, which also indicates the geometric dependence on divertor performance in the SAS divertor. Even with different strike point locations, complete divertor detachment with very low particle and heat fluxes at the divertor targets and a high confinement core with normalized energy confinement factor H 98 >1.0 can be simultanesouly achieved with the SAS divertor with ion B × ∇ B drift into SAS divertor, demonstrating the benefit of a closed divertor for exploration of core-edge integration.