Effect Of Inclination Research Articles

Effect of Bogie Cavity End Wall Inclination on Flow Field and Aerodynamic Noise in the Bogie Region of High-Speed Trains

Effect of Bogie Cavity End Wall Inclination on Flow Field and Aerodynamic Noise in the Bogie Region of High-Speed Trains

LATTICE BOLTZMANN ANALYSIS OF MIXED CONVECTION IN A LID-DRIVEN CAVITY WITH AN INNER HOT ELLIPTICAL BLOCK: EFFECT OF BLOCK INCLINATION

This study is a computational analysis of hydrodynamic and thermal behavior of combined natural and forced convection with a moving wall in a square enclosure containing an elliptical block. This inner block is exposed to a hot temperature. The enclosure is full of air which is cooled on its side walls by a low temperature. The remaining surfaces are thermally insulated, and the upper surface is sliding at a steady speed <i>u</i><sub>0</sub>. In particular, the impact of various factors related to geometry, such as the emplacement and the elliptical block inclination are analyzed for the range of the dimensionless parameter Richardson number (0.01 ≤ Ri ≤ 100) by using lattice Boltzmann method (LBM) with single relaxation time model (SRT). LBM offers the advantage of handling irregular geometries and curved boundaries without requiring complex mesh generation, simplifying computations, and reducing computational costs in comparison to the traditional methods. The findings are in the forms of streamlines, temperature contours, the mean Nusselt number, and the fluid mean temperature inside the enclosure. The results show that for the prevailing natural convection and for the centrally placed elliptical block, the dynamic and thermal fields are almost indicated by symmetry with regard to the mid-vertical of the enclosure. Moreover, the inclination of the elliptical block prevents the enhancement of the heat transfer for all positions of the block; except when the block is located close to the upper surface, the inclination improves the rate of heat transfer especially for Ri ≤ 1.

Recurrently Propagating Intensity Disturbances along Polar Plumes Observed in White Light and Extreme Ultraviolet

We study properties of intensity disturbances along polar coronal rays that are associated with plumes below. For this, we draw azimuth–time images of extreme ultraviolet (EUV) emission of 171 Å band observed by the SDO/AIA and white light (WL) observed by the SOHO/LASCO C2 in 2020 July. From the azimuth–time image, we define two tracks in which the EUV intensities were recurrently enhanced during two weeks. The two EUV tracks are rooted at 78.°8 and 81.°4 latitudes, but their projected azimuth angles are changed with time as the Sun rotates. Coherent WL tracks at different altitudes are determined by scaling the azimuth angles of the EUV tracks, accounting for the effect of inclination of coronal rays. From this, we construct time–distance images of WL intensities along WL tracks, whose projected azimuth angle changes along time and altitude, but the intensities are correlated with the EUV intensities measured below. The time–distance images of WL show repeated and inclined intensity features. The propagation speeds in the altitude range 2.3–6 solar radii are calculated to be 159 ± 8 km s−1 and 300 ± 24 km s−1. The EUV and WL intensities are found to be coherent at 1–2 day periods. It is also found that dynamic burst events along the EUV track are responsible for the enhanced emission. We conclude that the variation of the WL intensity along the polar coronal rays is related with the evolution of the EUV intensity below.

Effects of Inclination of Strip Entering into Roll-Bite on Warpage Behavior in Rolling

Effects of Inclination of Strip Entering into Roll-Bite on Warpage Behavior in Rolling

Numerical simulation study of enhanced convective heat transfer in the tube based on winglet vortex generator

In order to enhance the heat transfer effect and improve the energy utilization efficiency of the circular tube under turbulent flow, rhombic and triangular winglet vortex generators are proposed on the basis of rectangular winglet vortex generator. The effects of three vortex generators on flow and heat transfer in the tube are investigated by numerical simulations. The results indicate that, the rectangular and triangular winglets generate two pairs of longitudinal vortices and the triangular winglets generate four pairs of longitudinal vortices due to additional shrink-age regions. The multiple longitudinal vortices increase the mixing between the fluids, raise the temperature in the central region of the tube, and enhance the heat transfer effect. Furthermore, the triangular winglet enhanced tube has the largest direct flow area and the least effect on resistance. The triangular winglet enhanced tube had the best comprehensive performance, followed by the rhombic winglet enhanced tube, and finally, the rectangular winglet enhanced tube. The performance evaluation criterion reached 1.04-1.13, 1.05-1.15, and 1.08-1.21 for the three enhanced tubes in the given flow rate interval. In addition, the effect of inclination angle on the triangular winglet enhanced tube was further investigated, and the results show that the best comprehensive performance of enhanced heat transfer is achieved at an inclination angle of 45?, with a maximum performance evaluation criterion of 1.25.

Numerical simulation study of enhanced convective heat transfer in the tube based on winglet vortex generator

In order to enhance the heat transfer effect and improve the energy utilization efficiency of the circular tube under turbulent flow, rhombic and triangular winglet vortex generators are proposed on the basis of rectangular winglet vortex generator. The effects of three vortex generators on flow and heat transfer in the tube are investigated by numerical simulations. The results indicate that, the rectangular and triangular winglets generate two pairs of longitudinal vortices and the triangular winglets generate four pairs of longitudinal vortices due to additional shrinkage regions. The multiple longitudinal vortices increase the mixing between the fluids, raise the temperature in the central region of the tube, and enhance the heat transfer effect. Furthermore, the triangular winglet enhanced tube has the largest direct flow area and the least effect on resistance. The triangular winglet enhanced tube had the best comprehensive performance, followed by the rhombic winglet enhanced tube, and finally, the rectangular winglet enhanced tube. The performance evaluation criterion (PEC) reached 1.04-1.13, 1.05-1.15, and 1.08-1.21 for the three enhanced tubes in the given flow rate interval. In addition, the effect of inclination angle on the triangular winglet enhanced tube was further investigated, and the results show that the best comprehensive performance of enhanced heat transfer is achieved at an inclination angle of 45?, with a maximum PEC of 1.25.

Experimental Evaluations of Model Piles Subject to Inclined Loading in Sand

The structures that subjected to varying loads are supported by pile foundations. These loads consist of inclined and vertical loads. The main objective of this work is to experimentally investigate the effects of an inclined load on the lateral pile reaction and axial pile displacement for piles found in cohesionless soil. For this purpose, the slenderness ratios of model steel piles are varied by values of 11, 14, and 17. Moreover, the pile shapes involved in this study are H-pile, closed end circular and square. The experimental tests were conducted in sandy soil. However, the load inclination angle included in assessing the pile behavior were 0, 30, 45, and 60 from the vertical. In order to study the above parameters on the behavior of model pile, thirty-six experimental tests were carried out. Several findings indicated that the lateral pile deflection was highly influenced by increasing the load inclination. Further, the load inclination effect on the pile's ultimate bearing capacity is high which leads to a reduction in the pile's capacity. Additionally, the vertical displacement of pile is less than horizontal displacement when the pile is subjected to an inclined load of 45° and the model fails by horizontal displacement.

Dust- and inclination-corrected star formation and interstellar medium scaling relations in nearby galaxies

ABSTRACT Following from our recent work, we present a detailed analysis of star formation and interstellar medium (ISM) scaling relations, done on a representative sample of nearby galaxies. H α images are analysed in order to derive the integrated galaxy luminosity, known as a more instantaneous and accurate star formation rate (SFR) tracer, and the required photometric and structural parameters. Dust- and inclination-corrected H α luminosities, SFRs, and related quantities are determined using a self-consistent method based on previous work prescriptions, which does not require the assumption of a dust attenuation curve and use of Balmer decrements (or other hydrogen recombination lines) to estimate the dust attenuation, with the advantage of determining dust opacities and dust masses along the way. We investigate the extent to which the dust and inclination effects bias the specific parameters of these relations, the scatter and degree of correlation, and which relations are fundamental or are just a consequence of others. Most of our results are consistent with errors with other similar studies, while others come in opposition or are inconclusive. By comparing the B-band optical and H α (star-forming) discs scale lengths, we found on average the star formation distribution to be more extended than the stellar continuum emission one (the ratio being 1.10), this difference increasing with stellar mass. Similarly, more massive galaxies have a more compact stellar emission surface density than the star formation one (average ratio of 0.77). The method proposed can be applied in larger scale studies of star formation and ISM evolution, for normal low- to intermediate-redshift galaxies.

Failure behaviors of square-tunnel-structured rock specimens under various inclined boundary stress conditions

In most engineering practices, the directions of geo-stress are not always perpendicular or parallel to the center line of underground tunnels’ cross section, and the surrounding rocks are subjected to inclined boundary stresses, which is often ignored in most previous studies. The investigations on the failure characteristics of surrounding rocks around tunnels under inclined boundary stresses have great practical significance. In this study, a series of uniaxial or biaxial compression tests were conducted using cubic red sandstone specimens with different prefabricated square holes. The horizontal centerline inclinations of square holes were designed as 0°, 15°, 30°, and 45°. The test results show that the horizontal centerline inclinations of holes have a great impact on the strength of rock specimens which tend to increase firstly and followed by decreasing. The confining pressure stress σ2 amplify the horizontal centerline inclination effect of holes on the strength of rock specimens. In addition, the horizontal centerline inclination of holes also affected the failure mode and crack propagation of surrounding rock significantly, the stress concentration zone at the right-angle boundary of the hole can induce the propagation of cracks. The findings of this study may provide theoretical guidance and reference significance for the stability evaluation, support parameter and disaster control of underground tunnels.

Bone cuts-marks: the effect of inclination and lithic tool type on morphometric characteristics

The study of cut-marks on bones from archaeological complexes is required to reconstruct many aspects of societies’ activities, including hunting, economic and food activities of ancient humans. The profile of cut-marks can be influenced by shape of the tool edge and its inclination to the bone. To determine this influence an experimental modeling was carried out. Experimental lithic tools were used to produce cut-marks at 90˚ and 45˚ to the bone surface of the cleaned from meat domestic cow’s scapula. Classical statistical methods were applied to analyze the metric parameters and the opening angle. To analyze the shape without dimensional characteristics, the 2D geometric-morphometric analysis was used. Cross sections for geometric-morphometric analysis were obtained using an industrial profilometer. The results reveal that the type of stone tool and its position in the hand during operation significantly influence the shape and size of cut-marks. Perpendicular cutting marks are on average deeper and have a smaller opening angle than those produced by oblique cutting for the three cutting edge types. Several groups of cuts made by different types of blades, but at the same angle, have similar opening angles, while when one tool is held differently, the opening angles differ significantly. The cut-marks made with one-sided and two-sided retouched tools differ in size and opening angle at different inclinations of the tools, but have the similar shape. The traces made with an unretouched edge have different shape and size according to the inclination of the tool. This study is the first step to create a digital comparative collection of experimental cuts that will be used for further studies of cut-marks.

Design Parameters Investigation on Sand Transportation Characteristics of V-Inclined Pipe Based on Eulerian–Eulerian Two-Phase Flow Model

During the operation of the water transportation pipelines in the upstream of the Yellow River, varying degrees of sand deposition often occur under a low flow rate. Taking into account the effect of different pipe inclinations, pipe diameters, and inlet sand content, the Eulerian–Eulerian two-phase model was applied in the numerical simulation of sediment-laden flow in a V-inclined pipe. The results indicate that there is a significant difference between a V-inclined pipe and horizontal pipe affected by gravity. Compared with the downward inclined pipe, sand deposition is evident in the upward inclined pipe. The high-velocity region moves upward and the asymmetry of the cross-sectional velocity increases. As the pipe diameter increases, the interaction between sand and the wall as well as the degree of turbulence decrease, so that the distribution of sand volume concentration across the cross section will be more uniform. Under different inlet sand content, the lowest point of the pipe experiences the most sand deposition, with sand volume concentration and velocity distribution across the cross-sections becoming uneven as inlet sand content increases. The location of the maximum liquid velocity varies from section to section. When the inlet sand content increases from 0.42% to 5%, the liquid velocity of the pipe cross-section no longer satisfies the rule of high velocity for middle and low velocity near the wall.

The effect of different posterior inclinations of tibial component on tibiofemoral contact pressures after unicompartmental knee arthroplasty

BackgroundDifferent posterior inclinations of tibial component after unicompartmental knee arthroplasty (UKA) may lead to different biomechanical characteristics of the knee joint. This finite element study was designed to investigate the tibiofemoral contact pressures after UKA with different posterior inclinations of tibial component.MethodsFinite element model of a healthy knee joint was constructed, and mobile-bearing (MB) UKA models with 5 different posterior inclinations (3°, 5°, 7°, 9° and 11°) of tibial components were simulated. The maximum contact pressures of tibial plateau cartilage in the lateral compartment and polyethylene insert in the medial compartment were calculated based on the ground reaction force and the angle of the knee flexion obtained by 3D motion capture system.ResultsThe loading ratio of medial and lateral compartments during standing stance (medial 54.49%, lateral 45.51%) and tibial anterior displacement (134 N, 3.89 mm) of healthy knee was basically consistent with previous experimental data. The maximum contact pressures of the medial meniscus and lateral tibial plateau cartilage of the healthy knee during standing stance were 2.14 MPa and 1.57 MPa, respectively. At the static standing phase, the maximum contact pressures of the polyethylene insert decreased from 17.90 to 17.29 Mpa, and the maximum contact pressures of the tibial plateau cartilage in the lateral compartment increased from 0.81 to 0.92 Mpa following an increase in the posterior inclination of the tibial component. At the first peak of ground reaction force, the maximum contact pressures of polyethylene insert increased from 22.37 to 25.16 MPa, and the maximum contact pressures of tibial plateau cartilage in the lateral compartment increased from 3.03 to 3.33 MPa, with the increase in the posterior inclination of the tibial component. At the second peak of ground reaction force, the maximum contact pressures of polyethylene insert decreased from 2.34 to 2.22 MPa with the increase in posterior inclination of tibial component.ConclusionThe preoperative and postoperative finite element models of MB UKA were well established. The results showed that the maximum contact pressures of the polyethylene insert did not change significantly with the increase in the posterior inclination of the tibial prosthesis, while the maximum contact pressures of the tibial plateau cartilage of the lateral compartment increased when the posterior inclination of the tibial prosthesis was > 7°. Our results also show that the maximum contact pressures were greater with an excessive inclination angle (11°) of the tibial component, and the pressures of the tibial plateau cartilage in the lateral compartment were more concentrated on the posterior area. This study, therefore, proposes that excessive osteotomy should be avoided.

Entrepreneurial Inclination and Organisational Performance of Kenyan Small and Medium Enterprises: The Mediating Role of Business Model Innovation

This study investigated the effect of entrepreneurial inclination on Kenyan Small and Medium Enterprises (SMEs) performance and whether this effect was mediated through Business Model Innovation (BMI). Primary data were collected from a sample of 221 SMEs that had been ranked among the Top 100 medium enterprises in Kenya between 2008 and 2019 through Klynveld Peat Marwick Goerdeler (KPMG) and Nation Media Group yearly surveys. Data accepted from 134 top executives of the SMEs was analysed through regression analysis. The results revealed that entrepreneurial inclination indirectly influenced organisational performance through its positive effect on BMI. There was no evidence that entrepreneurial inclination independent of BMI influenced organisational performance. Thus, it was concluded that entrepreneurial inclination positively contributed to organisational performance through its favourable effect on BMI. The study adds to the literature on entrepreneurial inclination and organisational performance by linking them to BMI. The study advises industry practitioners and policymakers to encourage entrepreneurial conduct and BMI practices to improve organisational performance. Further studies are required to address the identified gaps.

Slug flow parameters applied to dynamic riser analysis

Slug flow is a typical pattern in the petroleum production system. Its main feature is intermittency. This feature influences the riser dynamic behavior due to the coupling of its geometric configuration and time and space variation of internal fluid parameters. Although the studies that illustrate slug flow intermittency and dynamic riser behaviors have been growing recently, this discussion still needs to be expanded. Most slug models proposed in the literature are simplified and do not adequately capture the intermittency to a proper riser dynamic influence determination. Previous models neglected at least one of the following slug flow mechanisms: random features, bubble shape, liquid slug aeration, wake, and pipeline inclination effects. This paper aims to cover all these phenomena and present a model that provides realistic slug flow data for any riser analysis program. The dynamic riser analysis is not the scope of this paper. This article used a new slug tracking model that captures the intermittency to study the influence of the internal flow over the dynamic riser behavior. The model considers the liquid slug hold-up and its change over the pipe, the oil and gas thermodynamic properties, and the geometrical transition from typically horizontal plane interfaces to vertical concentric bubble shapes. The slug tracking model tests use three gas and liquid ratios (0.55, 0.7, and 0.82) with a 2.05 m/s constant mixture velocity. The maximum relative pressure deviation was 24.1. Time and space analysis of the slug flow parameters demonstrates the slug tracking capacity to reproduce the intermittency of the bubble and liquid slug lengths, void fractions, velocities, and pressures. This intermittence is essential to describe the internal slug flow influence on the structure behavior.

CFD analysis of curvature and inclination effect on steam condensation in the presence of air

Steam-air condensation is one of the critical thermal–hydraulic phenomena in containment under accident conditions. Currently, sufficient experimental research and numerical analysis have been conducted on steam–air condensation outside the tube/plate. However, few studies have investigated the influence of curvature and inclination on condensation characteristics, and the local phenomena and mechanisms that affect the condensation process have not yet been fully revealed. In addition, it is of vital importance to evaluate the coupling effect between curvature and inclination in practical applications. To investigate the above-mentioned effects, numerical simulations were conducted over a wide parameter range (P = 0.2 ∼ 1.6 MPa, ωa = 0.1 ∼ 0.9, ΔT = 20 ∼ 100 K), and the related mechanisms were analyzed in detail. The results showed that there is a strong coupling relationship between curvature effect and inclination effect and the inflection point in the influence of inclination effect on steam condensation characteristics is discovered. Compared to the traditional conclusion that condensation capability gradually increases with the decrease of inclination angle. The effect of inclination on the condensation characteristics can reverse in different curvature regions. When the curvature is greater than 5 m−1, the inclination angle is negatively correlated with the condensation capability. When the curvature is less than 5 m−1, the inclination angle is positively correlated with the condensation capability. Furthermore, the enhancement effect originate from the curvature effect will greatly decrease as the inclination angle increases.

Influences of inclined crack defects on vibration characteristics of cylindrical roller bearings

Crack initiation and propagation directions on the raceway surface of cylindrical roller bearings (CRBs) can generate different forms of excitation patterns and affect the vibration level of CRBs. For inclined crack defects on the raceway surface, the direction of a roller passing through the cracked raceway determines the order and amplitude of time-varying displacement (TVD) excitation and time-varying stiffness (TVS) excitation. In this study, two different excitation modes are proposed to simulate the interactions between the roller and the raceway. Then, the excitation modes are integrated into the dynamic model of CRB and used to study the effects of crack inclination and propagation direction on the vibration characteristics of CRBs. The results show that the bearing vibration acceleration caused by excitation mode I is greater than that caused by excitation mode II. The distribution direction of the inclined crack defect on the CRB raceway has a great influence on its vibration level. It can provide useful guidance for early bearing fault detection and diagnosis.

Can we enable individuals to reach further down without rounding their backs before beginning a lift? Examining the influence of starting foot and trunk position on reach depth

There is disagreement regarding the efficacy of ‘safe’ lifting recommendations for reducing low back disorder risk. These recommendations commonly focus on minimising lumbar spine flexion, which limits the range of allowable starting lift positions for that person. This study evaluated whether starting postural adaptations could allow a person to reach down further without rounding their lumbar spine before beginning a lift. Reach displacement was measured as participants performed a series of maximal reach tasks under different combinations of stance width, foot orientation and trunk inclination, with their lumbar spine motion restricted. There were no interactions between any of the three postural adaptations or any effect of stance width or trunk inclination. Seventy-nine percent of participants achieved their greatest reach displacement with their feet externally rotated, which contributed to a 4 cm greater reach displacement compared to a neutral foot orientation (p < 0.001). Practitioner summary: This study examined whether aspects of initial posture could influence the ability to adhere to ‘safe’ lifting recommendations across a range of lift heights. As a component of lifting (re)training interventions, practitioners should consider starting lift posture adaptations (e.g. manipulating foot external rotation) to improve capacity to adhere to recommendations.

Effect of surface inclination on vertical loading rate and footstrike pattern in trail and road runners

Effect of surface inclination on vertical loading rate and footstrike pattern in trail and road runners

FEM Performance of Beam-Column Joint under Cyclic Loading with Column Inclination at Joint Portion

Outside non-ductile reinforced concrete (RC) beam-column connections are the primary subject of this article's analysis of their cyclic behaviour. This study utilizes experimental data and complex finite element simulations to probe the effect of angle inclination on the link. During the course of the experiment, both standard RC beam-column junction specimens and specimens with an angled column at the joint were tested. The samples were detailed for seismic activity. Physical test findings were contrasted with those obtained from computer-generated FEM simulations of similar specimens. In this research, we use the ANSYS software to perform in-depth 3D non-linear finite element (FE) simulations of beam-column junctions made of reinforced concrete (RC) at a range of inclinations. Beam-column specimens are subjected to cyclic loading in reverse with carefully calibrated amplitudes so that we can study how these parameters respond to repeated loading cycles. Finite element analysis results for energy dissipation and stiffness versus displacement are quite similar to experimental data. With its excellent ductile behaviour, ferrocement can be used as a hybrid reinforcing solution to improve the seismic performance of RC beam-column junctions. Analytical analyses supported the experimental research using finite element models developed with ANSYS software. The results show that the hysteresis simulation works well for both un-strengthened and ferrocement-strengthened specimens, proving its worth in practice.

Investigation of surface inclination effect during dropwise condensation of flowing saturated steam

When a pure vapor condenses over a surface, it can form a continuous liquid film or a multitude of discrete droplets, thus realizing the so-called dropwise condensation (DWC). In the literature, most of the experimental data refer to DWC on vertical condensing surfaces with quiescent vapor. However, in many applications, the condensing vapor usually has a non-zero flow velocity with a consequent effect on the sliding motion of droplets. Moreover, the drag force due to vapor velocity may be the only mechanism for liquid removal on a horizontal surface or in space applications. A systematic investigation of the effects of vapor drag and surface inclination on the heat transfer and droplet population during DWC is needed and is addressed in the present paper.Here, DWC of flowing steam is experimentally studied on sol-gel silica-based coated aluminium substrates at three different inclinations: vertical, inclined at 45°, and horizontal. Heat transfer coefficient (HTC) and droplet population measurements are performed in a wide range of heat flux (260–610 kW m−2) and average vapor velocity (3.3–13.8 m s−1). When decreasing the tilt angle, from vertical to horizontal, due to the lower contribution of the gravity force, the average droplet size increases, and a strong HTC reduction is observed above all at low vapor velocities. Because of the vapor drag force, the HTC increases with steam velocity and, at the highest mass velocity, the HTC is independent from the surface inclination. A model for the droplet departing radius in the presence of vapor velocity, initially proposed by the present authors for the sole case of vertical surfaces, is here modified to account also for the effect of surface inclination and then assessed against the present experimental data. Hence, we propose to predict the heat flux during DWC by coupling the new equation for the departing radius with the available models of heat transfer through a single droplet and drop-size distribution. The developed calculation method is found to provide satisfactory predictions of the HTC for the whole range of vapor velocity, heat flux and surface inclination.