Artykuły w czasopismach: „Double-cone flow”

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Kong, Wei Xuan, Rui Zhao, Jian Yu i Chao Yan. "Numerical Investigation of Hypersonic Double-Cone Flow". Applied Mechanics and Materials 232 (listopad 2012): 240–45. http://dx.doi.org/10.4028/www.scientific.net/amm.232.240.

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Hypersonic flow of Mach number 8 past a 25°-50° double cone geometry is numerically simulated at ReD=4.8E5. Complicated flow structures, including Type V shock-shock interaction, shock-boundary layer interaction, separation and reattachment at the corner are presented and discussed. The surface pressure and heat transfer rate distributions are also calculated and compared with the experimental data. Results show that both the 2nd order MUSCL and 5th order WENO could accurately reproduce the shock structures, while the higher order scheme could predict a more accurate size of separation zone. Generally, the size of the separation zone is underestimated with an overvalued pressure distribution after reattachment employing the full turbulent models. On the other hand, transition induced by the reattachment shock has been calculated using transition model and the results of pressure peak and the size of separation zone show good agreement with the experimental measurements.

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Nagata, Yasunori, Kazuhiko Yamada i Takashi Abe. "Hypersonic Double-Cone Flow with Applied Magnetic Field". Journal of Spacecraft and Rockets 50, nr 5 (wrzesień 2013): 981–91. http://dx.doi.org/10.2514/1.a32351.

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IGARASHI, Saburo. "Unsteady Separation on Double Cone in Hypersonic Rarefied Flow". Proceedings of the JSME annual meeting 2000.1 (2000): 759–60. http://dx.doi.org/10.1299/jsmemecjo.2000.1.0_759.

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Xu, Ying, Jun Da An, Zheng Hai Long i Yi Zhao. "Numerical Simulation and Optimum Design of a Double-Cone Flow Sensor". Applied Mechanics and Materials 220-223 (listopad 2012): 1892–97. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1892.

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This research based on a new type of Double-cone flow sensor, using computational fluid dynamics (CFD) method and orthogonal experiment to investigate the influence of key geometric factors, such as fore-and-aft cone angle, equivalent diameter ratio and channel flow length, on discharge coefficient, discharge coefficient linearity and relative pressure loss of double-cone flow sensor, and finally predict the best optimal match of these geometric factors. The turbulence model is RNG and the medium for simulation is water. After the simulation, a special device for calibration was set up to verify the computational conclusion. The results show that the biggest deviation of simulation on discharge coefficient linearity and relative pressure loss are less than 0.4% and 1.2%, the results simulated by CFD are in good agreement with that by experiment.

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Deng, Fei, Wei Xiong, Jianglei Zhou, Dandan Zheng, Xiaoyang Su i Yong Tang. "Experimental Study on Morphological Characteristics of Ventilated Supercavity of Double Disc Cavitator Projectile". Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 37, nr 1 (luty 2019): 93–99. http://dx.doi.org/10.1051/jnwpu/20193710093.

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Based on the principle of independence of cavity sections expansion, a double disc cavitator for underwater projectiles is proposed in this paper.The high-speed water tunnel experiment is carried out to study the generation and morphological characteristics of the ventilated supercavity which generated by this series of double disc cavitator.The experiment observed the ventilated supercavity morphology under the different cone angles by changing the ventilation flow coefficient.The experimental results show that there are two kinds of cavitation states:the front disc preferential cavitation and the rear disc preferential cavitation. The transition between these two states occur at a cone angle about 55°.The value of the critical ventilation flow coefficient when generating stable ventilation supercavity has a positive correlation with the cone angle.The front disc and the rear disc of the cavitator have mutual inhibitory effect on the production of ventilated supercavities.And the morphological characteristics of ventilated supercavity do not increase with the increasing of ventilation flow coefficient, but there is an upper limit value of ventilation flow coefficient.

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Gomes-Fernandes, R. "Flow features around double cones at hypersonic speed". Aeronautical Journal 117, nr 1193 (lipiec 2013): 741–48. http://dx.doi.org/10.1017/s000192400000840x.

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AbstractAn experimental study of double cone geometries in hypersonic flow (at M∞of 8·2 and Redof 0·36 × 106) was performed to provide additional data to a computational simulation study. In this study, depending on how the flow was initialised, the numerical solution yielded a violent pulsation mode of instability or a steady flow. Finally, an analysis of the shock oscillation was made and discussed.

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Gao, Jian, Jiaao Hao, Jingying Wang i Chunhian Lee. "Effect of Thermochemical Nonequilibrium Modeling on High-Enthalpy Double-Cone Flow". Journal of Spacecraft and Rockets 58, nr 4 (lipiec 2021): 1243–47. http://dx.doi.org/10.2514/1.a35002.

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Holloway, Michael E., Kyle M. Hanquist i Iain D. Boyd. "Assessment of Thermochemistry Modeling for Hypersonic Flow over a Double Cone". Journal of Thermophysics and Heat Transfer 34, nr 3 (lipiec 2020): 538–47. http://dx.doi.org/10.2514/1.t5792.

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Xiao, Hong, Yuhe Shang i Di Wu. "DSMC Simulation and Experimental Validation of Shock Interaction in Hypersonic Low Density Flow". Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/732765.

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Direct simulation Monte Carlo (DSMC) of shock interaction in hypersonic low density flow is developed. Three collision molecular models, including hard sphere (HS), variable hard sphere (VHS), and variable soft sphere (VSS), are employed in the DSMC study. The simulations of double-cone and Edney’s type IV hypersonic shock interactions in low density flow are performed. Comparisons between DSMC and experimental data are conducted. Investigation of the double-cone hypersonic flow shows that three collision molecular models can predict the trend of pressure coefficient and the Stanton number. HS model shows the best agreement between DSMC simulation and experiment among three collision molecular models. Also, it shows that the agreement between DSMC and experiment is generally good for HS and VHS models in Edney’s type IV shock interaction. However, it fails in the VSS model. Both double-cone and Edney’s type IV shock interaction simulations show that the DSMC errors depend on the Knudsen number and the models employed for intermolecular interaction. With the increase in the Knudsen number, the DSMC error is decreased. The error is the smallest in HS compared with those in the VHS and VSS models. When the Knudsen number is in the level of 10−4, the DSMC errors, for pressure coefficient, the Stanton number, and the scale of interaction region, are controlled within 10%.

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Zuo, Feng-Yuan, i Shu-Ling Hu. "Thermochemical non-equilibrium effects on aerothermodynamic prediction of laminar double-cone flow". Acta Astronautica 182 (maj 2021): 179–88. http://dx.doi.org/10.1016/j.actaastro.2021.01.058.

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MATSUMOTO, Hiroaki, i Jun SASO. "S191013 Monte Carlo simulation of hypersonic flow around a double cone configuration". Proceedings of Mechanical Engineering Congress, Japan 2011 (2011): _S191013–1—_S191013–2. http://dx.doi.org/10.1299/jsmemecj.2011._s191013-1.

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Pham, Hoang Son, Tatsuro Shoda, Takahiro Tamba, Akira Iwakawa i Akihiro Sasoh. "Impacts of Laser Energy Deposition on Flow Instability over Double-Cone Model". AIAA Journal 55, nr 9 (wrzesień 2017): 2992–3000. http://dx.doi.org/10.2514/1.j055670.

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Luo, Shi-chao, Li-yin Wu, Yu Chang i Xian Li. "Thermochemical non-equilibrium and electromagnetic effects of double-cone in hypervelocity flow". Aerospace Science and Technology 132 (styczeń 2023): 108041. http://dx.doi.org/10.1016/j.ast.2022.108041.

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Wang, Chuan Sheng, Shan Hu Li, Ping Fu i Chun Lei Lü. "3-D Flow Field Simulation for Extruding Part of Mixing-Extruding Machine". Applied Mechanics and Materials 44-47 (grudzień 2010): 122–26. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.122.

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The physical, mathematical and finite element model of the extruding part of mixing-extruding machine was established to carry on the finite element simulation of the extrusion part flow field. Results showed that the double cone screw have better mixing and feeding properties than single screw.

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Gong, Haifeng, Zhi Qiu, Ye Peng, Bao Yu, Zhixiang Liao, Ling Chen i Luo Xin. "Separation characteristics and structure optimization of double spherical tangent double-field coupling demulsifier". Journal of Petroleum Exploration and Production Technology 12, nr 4 (7.11.2021): 979–93. http://dx.doi.org/10.1007/s13202-021-01360-6.

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AbstractThe demulsification and dewatering of the W/O emulsion are widely used in petrochemical industry, oilfield exploitation, and resource and environmental engineering. However, efficiently treating emulsion via traditional single methods. In this study, a new double-field coupling demulsification and dewatering device is proposed, where the conical structure of the device is double spherical tangential type. The numerical model for double-field coupling is established, especially, the population balance model (PBM) is used to simulate the coalescence and breakup of dispersed droplets under the double-field coupling action. And the effects of three conical structures on the internal flow and separation efficiency are analyzed. Results show that the conical structure has a significant effect on the coalescence of droplets, especially the double spherical tangential cone is more conducive for improving the coalescence ability of small droplets and improving the separation efficiency of the device. After optimization, the optimal R value of the double spherical tangential coupling device is 300 mm, and the separation efficiency can be up to 96.32%, which is 6.13% higher than the separation efficiency of the straight double-cone coupling device.

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Lasater, Eric M., Richard A. Normann i Helga Kolb. "Signal integration at the pedicle of turtle cone photoreceptors: An anatomical and electrophysiological study". Visual Neuroscience 2, nr 6 (czerwiec 1989): 553–64. http://dx.doi.org/10.1017/s0952523800003497.

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AbstractThe morphology of the axon which connects the cell body and pedicle of turtle cone photoreceptors was studied by light and electron microscopy. The axon which contains numerous synaptic vesicles, some endoplasmic reticulum, and a few cisternae is basically filled with cytoplasm. The length of the axon is related to the class of cone and varies slightly with retinal location, with axons as short as 3–6 μm found in red cones, and as long as 60 μm in cones containing colorless oil droplets. By simultaneously voltage clamping the cell body and pedicle regions of single isolated cones, we measured the longitudinal axonal resistance and the cell body and pedicle membrane resistances. For each cell studied, the axonal resistance of cones with short axons was lower than the cell and pedicle membrane resistances. Thus, the cell can be considered to be an isopotential structure. However, in some cones with long axons, the axonal, cell body, and pedicle resistances were comparable. The pedicles of these cones, therefore, could act like summing points and may provide a locus for spatial signal integration. Electrical coupling between the principal and accessory members of double cones was also studied. Electron-microscopic observation of the membrane junction between the apposed inner segments of the double cones in the intact retina show narrow segments which resemble gap junctions. However, in every double cone studied in culture, passing currents into one member of the double cone did not result in measurable current flow in the adjacent cell. Thus, the two members of the double cone, isolated from the turtle retina, are not electrically coupled.

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Carpenter, Chris. "Adjustable Cone Meter Adapts Automatically to Wet-Gas Conditions". Journal of Petroleum Technology 74, nr 12 (1.12.2022): 61–63. http://dx.doi.org/10.2118/1222-0061-jpt.

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_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 207505, “Using an Adjustable Cone Meter To Measure Wet Gas,” by Sakethraman Mahalingam, SPE, Saudi Aramco; Gavin Munro, SPE, GM Flow Measurement; and Muhammad Arsalan, SPE, Saudi Aramco, et al. The paper has not been peer reviewed. _ A traditional fixed-size Venturi meter has a turndown of approximately 8:1 under dry-gas conditions that may drop to as low as 3:1 under wet-gas flow. When the well conditions change, a replacement of the original Venturi meter with one of a different size is needed. In the complete paper, the authors present the design, development, and testing of an adjustable cone meter that has the ability to adapt itself to flow conditions automatically and provide a turndown of as much as a 54:1 under dry-gas conditions and as much as 20:1 under wet-gas conditions. Adjustable Cone Meter Design The adjustable cone meter is a variation on a traditional differential pressure cone meter. A moveable sleeve is placed within the meter, and its position is moved using a rack-and-pinion arrangement. When the flow rate is high (Fig. 1a), the sleeve is downstream of the cone and the meter operates like a normal cone meter. This means that the differential pressure at the cone (P1–P2) is sufficiently high and within the measurable range of the meter. When the flow rate drops below a preset value, however, the differential pressure (P1–P2) drops below the measurable range of the meter. While a conventional cone meter would be unable to measure such flow rates, the adjustable cone meter is able to achieve accurate measurements because the meter detects that the differential pressure is below the measurable range and moves the sleeve automatically so that it covers the cone (Fig. 1b). This reduces the internal diameter of the flowline around the cone and causes the differential pressure to move into the measurable range. The meter then uses the differential pressure to again produce accurate flow measurements. In addition, the meter has a second differential pressure sensor downstream of the cone. This is used to measure the liquid fraction of the wet gas. Meter Design Exhaustive finite-element analysis (FEA) was conducted to determine the operating stresses within the meter body and its pressure-containing components during operation. The sliding sleeve can maintain full line pressure and features double-pressure seals at either end, safely containing fluids inside the flowline. The primary risk is the deformation and failure of the sliding sleeve because it is a thin metal structure. However, FEA established the minimum working pressure of at least 1,200 psi for the sleeve, gearbox, and meter body, using industry-standard safety factors. Cone meter calculations are provided in the complete paper.

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Chanda, Sourayon, i Peichun Amy Tsai. "Numerical Investigation of Diffusioosmotic Flow in a Tapered Nanochannel". Membranes 12, nr 5 (29.04.2022): 481. http://dx.doi.org/10.3390/membranes12050481.

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Diffusioosmosis concerns ionic flow driven by a concentration difference in a charged nano-confinement and has significant applications in micro/nano-fluidics because of its nonlinear current-voltage response, thereby acting as an active electric gating. We carry out a comprehensive computation fluid dynamics simulation to investigate diffusioosmotic flow in a charged nanochannel of linearly varying height under an electrolyte concentration gradient. We analyze the effects of cone angle (α), nanochannel length (l) and tip diameter (dt), concentration difference (Δc = 0–1 mM), and external flow on the diffusioosmotic velocity in a tapered nanochannel with a constant surface charge density (σ). External flow velocity (varied over five orders of magnitude) shows a negligible influence on the diffusioosmotic flow inside the tapered nanochannel. We observed that a cone angle causes diffusioosmotic flow to move towards the direction of increasing gap thickness because of stronger local electric field caused by the overlapping of electric double layers near the smaller orifice. Moreover, the magnitude of average nanoflow velocity increases with increasing |α|. Flow velocity at the nanochannel tip increases when dt is smaller or when l is greater. In addition, the magnitude of diffusioosmotic velocity increases with increasing Δc. Our numerical results demonstrate the nonlinear dependence of tapered, diffusioosmotic flow on various crucial control parameters, e.g., concentration difference, cone angle, tip diameter, and nanochannel length, whereas an insignificant relationship on flow rate in the low Peclet number regime is observed.

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Lani, Andrea, Marco Panesi i Herman Deconinck. "Conservative Residual Distribution Method for Viscous Double Cone Flows in Thermochemical Nonequilibrium". Communications in Computational Physics 13, nr 2 (luty 2013): 479–501. http://dx.doi.org/10.4208/cicp.160811.270212a.

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AbstractA multi-dimensionally upwind conservative Residual Distribution algorithm for simulating viscous axisymmetric hypersonic flows in thermo-chemical nonequilibrium on unstructured grids is presented and validated in the case of the complex flow-field over a double cone configuration. The resulting numerical discretization combines a state-of-the-art nonlinear quasi-monotone second order blended scheme for distributing the convective residual and a standard Galerkin formulation for the diffusive residual. The physical source terms are upwinded together with the convective fluxes. Numerical results show an excellent agreement with experimental measurements and available literature.

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Meena, Om Prakash, Pranitha Janapatla i Ganesh Kumar K. "Mixed convection flow over a vertical cone saturated porous medium with double dispersion effect". Applied Mathematics and Computation 430 (październik 2022): 127072. http://dx.doi.org/10.1016/j.amc.2022.127072.

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Meena, Om Prakash. "Mixed convection flow over a vertical cone with double dispersion and chemical reaction effects". Heat Transfer 50, nr 5 (5.02.2021): 4516–34. http://dx.doi.org/10.1002/htj.22086.

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Farmani, Zohreh, Jing Wang, Ralf Stannarius, Martina Bieberle, Frank Barthel, Uwe Hampel i Joshua A. Dijksman. "Improved evaluation of granular media flows using an X-ray scanning compatible cone-plate setup". EPJ Web of Conferences 249 (2021): 03020. http://dx.doi.org/10.1051/epjconf/202124903020.

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To understand the typically heterogeneous flowing behavior of granular materials, it is important to combine flow tests with three-dimensional imaging. To probe the flow behavior of granular materials over a wide range of flow rates, it is imperative to be able to impose such flow rates in a well controlled manner while performing imaging tests that are compatible with all imposed flow rates. Achieving both flow control and bulk imaging capacity is challenging for a number of reasons. Here, we describe the design of a setup in which we are able to do imaging while imposing a constant overall shear rate on a granular material. We characterize the setup in which flow tests will be performed, which consists of a bottom-driven cone-plate or double-cone design. We show that the setup can be integrated in x-ray microtomography devices to aid particle tracking based flow measurements. The design is also compatible with typical rheometer setups. We also perform high speed imaging of a granular flow in an ultra-fast x-ray scanner, for which we provide proof-of-principle data in a simplified shear setup. The designed flow geometry is also compatible with said high speed imaging facility, where particle image velocimetry can be employed to extract quantitative flow field data.

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Hao, Jiaao, i Chih-Yung Wen. "Numerical investigation of oxygen thermochemical nonequilibrium on high-enthalpy double-cone flows". International Journal of Heat and Mass Transfer 127 (grudzień 2018): 892–902. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2018.07.132.

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Narayana, Mahesha, i Precious Sibanda. "On the Solution of Double-Diffusive Convective Flow due to a Cone by a Linearization Method". Journal of Applied Mathematics 2012 (2012): 1–19. http://dx.doi.org/10.1155/2012/587357.

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The paper details the use of a nonperturbation successive linearization method to solve the coupled nonlinear boundary value problem due to double-diffusive convection from an inverted cone. Diffusion-thermo and thermal-diffusion effects have been taken into account. The governing partial differential equations are transformed into ordinary differential equations using a suitable similarity transformation. The SLM is based on successively linearizing the governing nonlinear boundary layer equations and solving the resulting higher-order deformation equations using spectral methods. The results are compared with the limited cases from previous studies and results obtained using the Matlab inbuiltbvp4cnumerical algorithm and a shooting technique that uses Runge-Kutta-Fehlberg (RKF45) and Newton-Raphson schemes. These comparisons reveal the robustness and validate the usage of the linearisation method technique. The results show that the nonperturbation technique in combination with the Chebyshev spectral collocation method is an efficient numerical algorithm with assured convergence that serves as an alternative to numerical methods for solving nonlinear boundary value problems.

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Meena, Om Prakash. "Influence of Injection/Suction on Mixed Convection Flow Across a Vertical Cone Saturated Porous Medium with Double Dispersion and Chemical Reaction Effects". Tecnica Italiana-Italian Journal of Engineering Science 65, nr 2-4 (30.07.2021): 433–41. http://dx.doi.org/10.18280/ti-ijes.652-442.

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We examined how injection/suction impacts the flow characteristics for mixed convection across a vertical cone saturated porous medium in the presence of double dispersion and chemical reaction effects. We perform suitable transformations to convert the nonlinear system of partial differential expressions into a system of non-dimensional form and received dimensionless equations solved numerically by the bivariate Chebyshev spectral collocation quasi-linearization method. We explain the outcomes of the flow characteristics over various variables through diagrams and numerical benchmarks. We also establish precision verification of the chosen numerical technique through a comparison with prior published computations and found to be in great assent. The residual analysis section also illustrated which unblocks convergence of the present results.

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Ma, Yarui, Jiwen Cui i Jiubin Tan. "Quantitative Expression of a Slight Deviation of the Impact Angle in a Collision Atomizer". Machines 10, nr 9 (5.09.2022): 771. http://dx.doi.org/10.3390/machines10090771.

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In the processing of colliding atomizers, a small change in the inclination of each orifice will double the impact angle, seriously affecting its atomization performance. In this paper, the influence of slight impact angle deviation on atomization performance was studied in steps of 1°, quantitatively, for the first time. The cavitation effect of the flow field was combined with the shape and parameters of the atomization field. FLUENT was used to simulate the internal flow field, and an independently designed atomizer with transparent nozzles was used to detect the internal flow field in real time. The collision atomization experimental platform and the laser interference particle measurement platform were built independently, and the collision angle was adjusted through a high-precision rotating table to establish the relationship between collision-angle deviation (60° ± 5°) and the atomization field performance (Sauter mean diameter, atomization cone angle, and spatial distribution of droplets). The experimental results showed that under the same injection pressure, the increase in the collision angle led to an decrease in the Sauter mean diameter and an increase in the atomization cone angle. Taking 60° as the benchmark, the particle size distribution was concentrated at ~150 μm to 300 μm within the variation range of ±2°, and the peak positions were very similar.

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PEREIRA, J. C. F., i J. M. M. SOUSA. "Confined vortex breakdown generated by a rotating cone". Journal of Fluid Mechanics 385 (25.04.1999): 287–323. http://dx.doi.org/10.1017/s002211209900436x.

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Confined vortex breakdown generated by a rotating cone within a closed cylindrical container has been studied both by numerical simulation and by experimental techniques. A comprehensive investigation of the various flow regimes has been carried out by flow visualization. From laser–Doppler measurements of the entire flow field (three velocity components) detailed maps of the time-averaged flow structures for single and double breakdown have been constructed. Three-dimensional time-dependent simulations of steady and unsteady breakdown have been performed. Steady numerical and experimental flow fields obtained at Reynolds number 2200 for a gap ratio of 2 show notable agreement. At critical Reynolds numbers of approximately 3095, for a gap ratio of 2, and 2435, for a gap ratio of 3, the flow was observed becoming unsteady. The periodic behaviour exhibited by the unsteady flow suggested the occurrence of a supercritical Hopf bifurcation. This conjecture was confirmed by the evolution of the oscillation amplitude as a function of criticality, measured for a gap ratio of 3. The dynamical behaviour of unsteady vortex breakdown structures is depicted by numerical simulation of two distinct oscillatory regimes, at Reynolds numbers 2700 and 3100. A thorough analysis of the numerical results has shown that whereas the former regime is characterized by the steady oscillation of closely axisymmetric breakdowns, the latter displays precession of breakdown structures about the central axis. Additionally, it was observed that the mode bringing about the Hopf bifurcation is non-axisymmetric, with azimuthal periodicity of π/2 radians. From examination of measured velocity power spectra at higher Reynolds numbers, a transition scenario was also educed. In the present case, the Ruelle–Takens–Newhouse theorem has been shown to apply.

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Gontu, Vamsi, Pervinder Bhogal i Patricius A. Brouwer. "Dual flow diversion stents for aneurysm treatment in a partial unfused basilar artery". Interventional Neuroradiology 21, nr 6 (22.10.2015): 669–73. http://dx.doi.org/10.1177/1591019915609135.

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Unfused basilar arteries, frequently but erroneously referred to as ‘fenestrations’, are not uncommonly associated with aneurysms. The difficulty in treating these aneurysms lie in the fact that they are often wide necked and frequently incorporate both channels of the unfused segment, with varying calibres of the channels, necessitating technically challenging treatment strategies. It is important to preserve both channels because of the potential presence of perforating arteries originating from these segments. There are numerous case reports of such aneurysms being treated by coils alone, coiling with balloon assistance and stent-assisted coiling in configurations such as ‘X’, ‘double barrel’ or waffle cone. We present an exemplary case, in which an aneurysm on a partial unfused basilar segment was treated with parallel flow diverters with an excellent result on follow-up imaging.

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CAMASSA, ROBERTO, TERRY JO LEITERMAN i RICHARD M. MCLAUGHLIN. "Trajectory and flow properties for a rod spinning in a viscous fluid. Part 1. An exact solution". Journal of Fluid Mechanics 612 (10.10.2008): 153–200. http://dx.doi.org/10.1017/s0022112008000918.

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An exact mathematical solution for the low-Reynolds-number quasi-steady hydrodynamic motion induced by a rod in the form of a prolate spheroid sweeping a symmetric double cone is developed, and the influence of the ensuing fluid motion upon passive particles is studied. The resulting fluid motion is fully three-dimensional and time varying. The advected particles are observed to admit slow orbits around the rotating rods and a fast epicyclic motion roughly commensurate with the rod rotation rate. The epicycle amplitudes, vertical fluctuations, arclengths and angle travelled per rotation are mapped as functions of their initial coordinates and rod geometry. These trajectories exhibit a rich spatial structure with greatly varying trajectory properties. Laboratory frame asymmetries of these properties are explored using integer time Poincaré sections and far-field asymptotic analysis. This includes finding a small cone angle invariant in the limit of large spherical radius whereas an invariant for arbitrary cone angles is obtained in the limit of large cylindrical radius. The Eulerian and Lagrangian flow properties of the fluid flow are studied and shown to exhibit complex structures in both space and time. In particular, spatial regions of high speed and Lagrangian velocities possessing multiple extrema per rod rotation are observed. We establish the origin of these complexities via an auxiliary flow in a rotating frame, which provides a generator that defines the epicycles. Finally, an additional spin around the major spheroidal axis is included in the exact hydrodynamic solution resulting in enhanced vertical spatial fluctuation as compared to the spinless counterpart. The connection and relevance of these observations with recent developments in nano-scale fluidics is discussed, where similar epicycle behaviour has been observed. The present study is of direct use to nano-scale actuated fluidics.

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BEN-DOR, G., E. I. VASILIEV, T. ELPERIN i A. CHPOUN. "Hysteresis phenomena in the interaction process of conical shock waves: experimental and numerical investigations". Journal of Fluid Mechanics 448 (26.11.2001): 147–74. http://dx.doi.org/10.1017/s0022112001006085.

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The interaction of two conical shock waves, one converging and straight and the other diverging and curvilinear, in an axisymmetric flow was investigated both experimentally and numerically. A double-loop hysteresis was discovered in the course of the experimental investigation. The double-loop hysteresis consisted of a major one, associated with the interaction between the boundary layer and the wave configuration, and a minor one, associated with the dual-solution phenomenon, which is known to be non-viscous-dependent. The minor hysteresis loop was found to be an internal hysteresis loop of the major one. As expected the numerical Euler calculations failed to detect the viscous-dependent major hysteresis loop but did succeed in obtaining the non-viscous-dependent minor (internal) hysteresis loop. In addition, multiple hysteresis loops, associated with the interaction between the shock wave configuration and the edge of the curvilinear mobile cone were also observed. The non-viscous minor hysteresis loop involved different overall shock wave reflection configurations, and the other hysteresis loops involved the same shock wave reflection configuration but different flow patterns.

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Wójcik, Michał, Johannes Härtl, Jin Y. Ooi, Michael Rotter, Songxiong Ding i Gisle G. Enstad. "Experimental Investigation of the Flow Pattern and Wall Pressure Distribution in a Silo with a Double-Cone Insert". Particle & Particle Systems Characterization 24, nr 4-5 (listopad 2007): 296–303. http://dx.doi.org/10.1002/ppsc.200601120.

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Xu, Ying, Xiang Hong Zhang, Tao Zhang i Lu Gao. "Optimum Design of a Screw-In Venturi Flow Sensor". Applied Mechanics and Materials 401-403 (wrzesień 2013): 1082–86. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.1082.

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To study discharge coefficient linearity of screw-in venturi flow sensor, the effect of the screw-in blade attached to the sensor on discharge coefficient was analyzed, the structure of the screw-in blade was optimized by CFD software. Through the observation of velocity field, it was found that discharge coefficient will basically remain unchanged at low Reynolds number, while it declines greatly at high Reynolds number because of the guidance of the screw-in blade, as a result discharge coefficient linearity becomes better at the same measurement range. Orthogonal array of DN100 was designed for 10:1 measurement range to explore effect of geometric parameters of the screw-in blade on discharge coefficient linearity. Optimum structure for the screw-in blade is determined as follows: number of blade is 4, back slip angle of blade is 50°, front slip angle of blade is 5° and height of blade is 10.5mm. The numerical simulation indicates discharge coefficient linearity of the optimal screw-in venturi flow sensor is 0.601%,which is better than that of double-cone venturi flow sensor.

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BILLINGHAM, JOHN. "Surface-tension-driven flow in fat fluid wedges and cones". Journal of Fluid Mechanics 397 (25.10.1999): 45–71. http://dx.doi.org/10.1017/s0022112099006047.

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We consider the evolution under the action of surface tension of wedges and cones of viscous fluid whose initial semi-angles are close to π/2. A short time after the fluid is released from rest, there is an inner region, where surface tension and viscosity dominate, and an outer region, where inertia and viscosity dominate. We also find that the velocity of the tip of the wedge or cone is singular, of O(log(1/t)), as time, t, tends to zero. After a long time, the free surface asymptotes to a similarity form where deformations are of O(t2/3), and capillary waves propagate away from the tip. However, a distance of O(t3/4) away from the tip, viscosity acts to damp out the capillary waves.We solve the linearized governing equations using double integral transforms, which we calculate numerically, and use asymptotic techniques to approximate the solutions for small and large times. We also compare the asymptotic solution for the inviscid fat wedge with a numerical solution of the nonlinear inviscid problem for wedges of arbitrary semi-angle.

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Jasmine Benazir, A., R. Sivaraj i Oluwole Daniel Makinde. "Unsteady Magnetohydrodynamic Casson Fluid Flow over a Vertical Cone and Flat Plate with Non-Uniform Heat Source/Sink". International Journal of Engineering Research in Africa 21 (grudzień 2015): 69–83. http://dx.doi.org/10.4028/www.scientific.net/jera.21.69.

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The present study focuses the effects of double dispersion, non-uniform heat source/sink and higher order chemical reaction on unsteady, free convective, MHD Casson fluid flow over a vertical cone and flat plate saturated with porous medium. The extensively validated and unconditionally stable numerical solutions are obtained for the governing equations of two dimensional boundary layer flow by using the finite difference scheme of Crank-Nicolson type. The behavior of velocity, temperature and concentration distributions for various controlling parameters of this problem are graphically illustrated and discussed in detail. The average skin friction, Nusselt number and Sherwood number for sundry parameters are presented in tables. Results indicate that an increase in Casson fluid parameter is found to decelerate fluid flow by increasing the plastic dynamic viscosity whereas it enhances the shear stress in the flow regime. The temperature-dependent heat source/sink plays a vital role on controlling the heat transfer however the surface-dependent heat source/sink also has notable influence on the heat transfer characteristics. It is to be noted that higher order chemical reaction has the tendency to dilute the influence of chemical reaction parameter on the species concentration.

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Korobko, I. V., A. V. Pysarets i A. M. Rak. "Estimation of Factors that Affect the Metrological Characteristics of Target Flow Meters". Metrology and instruments, nr 6 (11.01.2020): 27–34. http://dx.doi.org/10.33955/2307-2180(6)2019.27-34.

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The article is devoted to the effective system creation for recording liquids and gases flows. There is extremely relevant for creating metering units of fuel and energy resources. The aim of the work is to determine the influence of the flowed body geometric configuration of the sensitive element and its orientation relative to the direction of the flow on the hydrodynamic flow meter metrological characteristics, as well as determining the instruments’ rational location in the technological line Based on the example of the hydrodynamic class measuring transducers factors that have a significant impact on their metrological characteristics are determined, the degree of the transducers sensitivity to the measured medium flows asymmetry is revealed. The flows asymmetry is simulated by hydraulic resistances of different spatial configurations (spatial elbow, elbow, double elbow, contraction, abrupt contraction). Simulation modeling of the operation of such devices is performed. Sensitive elements of different Gaussian curvatures such as zero (cylinder), positive (cone) and negative (hollow hemisphere) were studied. The value of the registration result uncertainty depends on the flow asymmetry and the instrument spatial orientation relative to the vertical axis in the technological network. The obtained results make it possible to clearly determine the instrument installation place in the technological network under conditions of maximum accuracy and minimal impact on the measured medium. This allows effectively using transducers in places of the technological network, taking into account the specific conditions for the metering units creation. There is no necessary to make straight pipeline sections before and after the instruments. The researches results show that measuring instruments with flow bodies in the shape of a cone oriented the apex toward the flow are the best.

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FEI, YIJIAN, i THOMAS E. HUGHES. "Transgenic expression of the jellyfish green fluorescent protein in the cone photoreceptors of the mouse". Visual Neuroscience 18, nr 4 (lipiec 2001): 615–23. http://dx.doi.org/10.1017/s0952523801184117.

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The goal of this study was to determine whether the jellyfish green fluorescent protein (GFP) could be used in transgenic mice to label and purify cone photoreceptors from the living retina. We created a transgene containing the 5′ regulatory sequence of the human red pigment gene (pR6.5 lacZ clone; kindly provided by J. Nathans & Y. Wang), fused to the GFP coding sequence. This transgene was used to generate seven lines of PCR-positive founders. Three of the lines had bright green fluorescent cone photoreceptors. The GFP fills the entire cell. Two mouse lines had only a few (∼10–100) fluorescent cells per retina, and one line (R6.85933) had many thousands. In the latter, double labeling of the cones with RITC-conjugated peanut agglutinin reveals that in the ventral retina a small proportion of the cones express GFP, while in the dorsal retina the majority do. Cells dissociated from the retinae of line R6.85933 continue to fluoresce and can be readily detected and enriched with flow cytometry. The signal provides a log unit of separation between the fluorescent cone soma and the remaining retinal cells. Roughly 3% of the cells are this fluorescent, and it is possible to purify up to 30,000 cells from one mouse. RT-PCR analysis of the mRNA from these isolated cells detects both the middle and short wavelength opsins with little if any contamination from rhodopsin.

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Joßberger, Simon, i Stefan Riedelbauch. "Scale-Resolving Hybrid RANS-LES Simulation of a Model Kaplan Turbine on a 400-Million-Element Mesh". International Journal of Turbomachinery, Propulsion and Power 8, nr 3 (2.08.2023): 26. http://dx.doi.org/10.3390/ijtpp8030026.

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Double-regulated Kaplan turbines with adjustable guide vanes and runner blades offer a high degree of flexibility and good efficiency for a wide range of operating points. However, this also leads to a complex geometry and flow guidance with, for example, vortices of different sizes and strengths. The flow in a draft tube is especially challenging to simulate mainly due to flow phenomena, like swirl, separation and strong adverse pressure gradients, and a strong dependency on the upstream flow conditions. Standard simulation approaches with RANS turbulence models, a coarse mesh and large time step size often fail to correctly predict performance and can even lead to wrong tendencies in the overall behavior. To reveal occurring flow phenomena and physical effects, a scale-resolving hybrid RANS-LES simulation on a block structured mesh of about 400 million hexahedral elements of a double-regulated five-blade model Kaplan turbine is carried out. In this paper, first, the results of the ongoing simulation are presented. The major part of the simulation domain is running in LES mode and seems to be properly resolved. The validation of the simulation results with the experimental data shows mean deviations of less than 0.8% in the global results, i.e., total head and power, and a good visual agreement with the three-dimensional PIV measurements of the velocity in the cone and both diffuser channels of the draft tube. In particular, the trend of total head and the results for the draft tube differ significantly between the scale-resolving simulation and a standard RANS simulation. The standard RANS simulation exhibits a highly unsteady behavior of flow, which is not observed in the experiments or scale-resolving simulation.

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Do¨bbeling, K., H. P. Kno¨pfel, W. Polifke, D. Winkler, C. Steinbach i T. Sattelmayer. "Low-Nox Premixed Combustion of MBtu Fuels Using the ABB Double Cone Burner (EV Burner)". Journal of Engineering for Gas Turbines and Power 118, nr 1 (1.01.1996): 46–53. http://dx.doi.org/10.1115/1.2816548.

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A novel combustion technique, based on the Double Cone Burner, has been developed and tested. NOx emissions down to very low levels are reached without the usual strong dilution of the fuel for MBtu syngases from oxygen-blown gasification of coal or residual oil. A limited amount of dilution is necessary in order to prevent ignition during the mixing of fuel and combustion air. The relevant properties of the fuel are reviewed in relation to the goal of achieving premixed combustion. The basic considerations lead to a fuel injection strategy completely different from that for natural gas. A high-speed premixing system is necessary due to the very short chemical reaction times of MBtu fuel. Fuel must be prevented from forming ignitable mixtures inside the burner for reliability reasons. A suitable fuel injection method, which can be easily added to the ABB double cone burner, is described. In common with the design of the standard EV burner, the MBtu EV burner with this fuel injection method is inherently safe against flashback. Three-dimensional flow field and combustion modeling is used to investigate the mixing patterns and the location of the reaction front. Two burner test facilities, one operating at ambient and the other at full gas turbine pressure, have been used for the evaluation of different burner designs. The full-pressure tests were carried out with the original gas turbine burner size and geometry. Combining the presented numerical predictive capabilities and the experimental test facilities, burner performance can be reliably assessed for a wide range of MBtu and LBtu fuels (residue oil gasification, waste gasification, coal gasification, etc.). The atmospheric tests of the burner show NOx values below 2 ppm at an equivalence ratio equal to full-load gas turbine operation. The NOx increase with pressure was found to be very high. Nevertheless, NOx levels of 25 vppmd (@ 15 percent O2) have been measured at full gas turbine pressure. Implemented into ABB’s recently introduced gas turbine GT13E2, the new combustion technique will allow a more straightforward IGCC plant configuration without air extraction from the gas turbine to be used.

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Carral, Sandra, Christophe Vergez i Cornelis Nederveen. "Toward a Single Reed Mouthpiece for the Oboe". Archives of Acoustics 36, nr 2 (1.05.2011): 267–82. http://dx.doi.org/10.2478/v10168-011-0021-0.

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AbstractReed woodwind instruments differ in both their geometry (mainly cylindrical or mainly conical) and their excitation mechanism (single or double reed). How much of the resulting sound is due to the single/double reed, and how much to the geometry of the instrument? Measurements done by Almeidaet al.(J. Acoust. Soc. Am.,121, 1, 536-546, 2007) show that the flow vs pressure characteristic curve of an oboe reed is not that different from that of a clarinet reed, the only difference probably being due to pressure recovery inside the conical staple. Is it possible to make a single reed mouthpiece for an oboe, while keeping the conical staple, that would still give the oboe its characteristic sound? To find it out, a mouthpiece with the following characteristics was made: A standard clarinetBb reed can be attached to it, its volume is approximately that of the missing part of the instrument cone, and a standard French oboe staple can be inserted to it, so that it can be inserted in the usual way in any french oboe. In this paper, the first prototype of the mouthpiece is shown. Also, a sound comparison of the oboe sounds played with this mouthpiece and a standard double reed by a professional player is presented.

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Khan, Najeeb Alam, i Faqiha Sultan. "On the double diffusive convection flow of Eyring-Powell fluid due to cone through a porous medium with Soret and Dufour effects". AIP Advances 5, nr 5 (maj 2015): 057140. http://dx.doi.org/10.1063/1.4921488.

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Mallikarjuna, B., Rangaswamy i Ahmed Kadhim Hussein. "Effect of Higher Order Chemical Reaction on Double Diffusive Mixed Convective Flow Over a Rotating Vertical Cone in a Darcy Porous Medium". Research Journal of Science and Technology 9, nr 3 (2017): 416. http://dx.doi.org/10.5958/2349-2988.2017.00073.0.

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RamReddy, Ch, i Ch Venkata Rao. "Double Stratification Effects on Mixed Convection Boundary Layer Flow of a Nanofluid Over Vertical Frustum of a Cone: A Darcy-Forchheimer Model". Journal of Nanofluids 6, nr 5 (1.10.2017): 971–81. http://dx.doi.org/10.1166/jon.2017.1391.

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Sandeep Kumar Choubey i C.K. Niraj. "Procedure for mix designing used for steel fibre reinforced self-compacting concrete". International Journal of Science and Research Archive 8, nr 1 (28.02.2023): 793–803. http://dx.doi.org/10.30574/ijsra.2023.8.1.0126.

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This work focuses on a methodical design process for developing self-compacting concrete (SFRSCC) using steel fibre reinforcements. The objective is to create a self-consolidating concrete that has the double advantage of self-consolidating characteristics and composite toughness. Experimental modelling involved building the mortar phase with manufactured sand (M-sand) as fine aggregate utilising a systematic mix design process based on the particle packing idea. Optimisation of aggregates was determined using the packing density idea and slump cone research. By conducting a paste consistency test, cement and ground granulated blast furnace slag (GGBFS) powder combinations were chosen. Finally, the amount of superplasticizer was determined based on Marsh cone experiments and the percentage by volume of steel fibres determined by slump flow research. The addition of steel fibre dosage impacts the workability of both standard and high strength concrete, and the fresh properties emphasised the necessity to maintain a large paste volume for increased workability. On the basis of the recommended mix design technique using M-sand, self-compacting concrete with a maximum strength of 70MPa was manufactured. On the other hand, experimental studies on the fresh and hardened properties of recommended self-compacting steel fibre concrete mixes were presented. In addition, test findings demonstrated the viability of employing M-sand as a replacement for river sand in its entirety.

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Otegbeye, Olumuyiwa, Sandile S. Motsa i Md Sharifuddin Ansari. "An application of paired quasilinearization on double-diffusive convection flow over a cone embedded in a porous medium in the presence of nanoparticles". Heat Transfer-Asian Research 48, nr 4 (10.03.2019): 1413–39. http://dx.doi.org/10.1002/htj.21439.

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Wang, Jingzhe, Siyu Zhang, Liang Jiang, Shesh Srivatsa i Zaiwang Huang. "Prediction of Grain Size in a High Cobalt Nickel-Based Superalloy". Materials 16, nr 17 (23.08.2023): 5776. http://dx.doi.org/10.3390/ma16175776.

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With the advancement in computational approaches and experimental, simulation, and modeling tools in recent decades, a trial-and-validation method is attracting more attention in the materials community. The development of powder metallurgy Ni-based superalloys is a vivid example that relies on simulation and experiments to produce desired microstructure and properties in a tightly controlled manner. In this research, we show an integrated approach to predicting the grain size of industrial forgings starting from lab-scale cylindrical compression by employing modeling and experimental validation. (a) Cylindrical compression tests to obtain accurate flow stress data and the hot working processing window; (b) double-cone tests of laboratory scale validation; (c) sub-scale forgings for further validation under production conditions; and (d) application and validation on full-scale industrial forgings. The procedure uses modeling and simulation to predict metal flow, strain, strain rate, temperature, and the resulting grain size as a function of thermo-mechanical processing conditions. The models are calibrated with experimental data until the accuracy of the modeling predictions is at an acceptable level, which is defined as the accuracy at which the results can be used to design and evaluate industrial forgings.

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Ito, Atsushi, Philipp Oetinger, Ryosuke Tasaki, Oliver Sawodny i Kazuhiko Terashima. "Visual Nonlinear Feedback Control of Liquid Level in Mold Sprue Cup by Cascade System with Flow Rate Control for Tilting-Ladle-Type Automatic Pouring System". Materials Science Forum 925 (czerwiec 2018): 483–90. http://dx.doi.org/10.4028/www.scientific.net/msf.925.483.

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This paper presents the novel approach of liquid level control of mold sprue cup using camera information for tilting-ladle-type automatic pouring system in casting industry. A liquid level in mold sprue cup should be kept at high position to avoid inclusion of oxides and dusts during pouring process. A cascade control system with double feedback loop to enhance control response was proposed for the present level control: inner loop was the flowrate control system for pouring ladle, and outer loop was the level control one with camera measurement to detect the liquid level. The control part of flow rate was constructed based on the past study. The mathematical model of liquid behavior in a sprue cup of an inverted cone shape was built in this paper. The level controller was newly designed based on nonlinear control theory by exact linearization. The effectiveness of the proposed cascade system was verified by control simulations.

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Pasha, Amjad A., i Khalid A. Juhany. "Effect of wall temperature on separation bubble size in laminar hypersonic shock/boundary layer interaction flows". Advances in Mechanical Engineering 11, nr 11 (listopad 2019): 168781401988555. http://dx.doi.org/10.1177/1687814019885556.

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At hypersonic speeds, the external wall temperatures of an aerospace vehicle vary significantly. As a result, there is a considerable heat transfer variation between the boundary layer and the wall of the hypersonic vehicle. In this article, numerical computations are performed to investigate the effect of wall temperature on the separation bubble length in laminar hypersonic shock-wave/boundary-layer interaction flows over double-cone configuration at the Mach number of 12.2. The flow field is described in detail in terms of different shocks, expansion fans, shear layer and separation bubble. The variation of the Prandtl number has a negligible effect on the flow field and wall data. A specific heat ratio of less than 1.4 results in the better prediction of wall pressure and heat flux in the shock/boundary-layer interaction region. It is observed that as the wall temperature is increased, the separation bubble size and hence the separation shock length increases. The high firmness of the laminar boundary-layer at a high Mach number shows that the wall temperature in the shock/boundary-layer interaction region has little effect. The peak wall pressure and heat flux decrease with an increase in wall temperature. An estimation is developed between separation bubble length and wall temperature based on the computed results.

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Zhu, Yang-Zhu, Shi-He Yi, Lin He, Li-Feng Tian i Yong-Wei Zhou. "Instantaneous and time-averaged flow structures around a blunt double-cone with or without supersonic film cooling visualized via nano-tracer planar laser scattering". Chinese Physics B 22, nr 1 (styczeń 2013): 014702. http://dx.doi.org/10.1088/1674-1056/22/1/014702.

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Salvador, Monica Martins Silva, Sigrid Köhne, John Maximilian Köhne, Bernd Lennartz i Paulo Leonel Libardi. "Dye tracer and morphophysical properties to observe water flow in a Gleyic Luvisol". Scientia Agricola 68, nr 2 (kwiecień 2011): 160–66. http://dx.doi.org/10.1590/s0103-90162011000200005.

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The understanding of the preferential water flow and solute transport is important with regard to losses of nutrients and pesticides that affect the quality of the groundwater or surface water resources. Experiments using the brilliant blue dye tracer, a tension infiltrometer (TI) and a double square infiltrometer (DI) were carried out in the experimental field site located around 15 km southeast of the city of Rostock (North-Eastern Germany) on arable land in a Pleistocene lowland landscape where corn (Zea mays L.) and barley (Hordeum spp.) had been cultivated. One day after dye the infiltration, a pit was dug and vertical profiles were prepared in the TI and DI sites to assess the dye pathways in the subsoil of a Gleyic Luvisol. We wanted to examine if the mottled red and white (bleached) colour-pattern of the Gleyic Luvisol subsoil resulting from temporally stagnant water could be related to flow paths as visualized by dye tracing and if the soil colour could be related to other physical soil properties. Biogenic soil structures were the main transport routes conducting water and solutes into great depth in short time. These pathways had lower bulk density and less cone resistance than the adjacent red or white (bleached) areas of the Gleyic Luvisol subsoil. The red areas were involved in transport because their water contents increased after as compared to before infiltration. However, the measured physical soil properties did not differ between white and red areas. We assume that red areas participate in transport at least by imbibing water from the adjacent biogenic flow paths.

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Zhang, Qun, Xin Wang, Rui Kou, Chaochao Li, Peng Zhang, Han Hai, Chenghao Li, Fuzheng Yang, Qiang Liu i Tingting Cao. "Numerical study on pre-film atomization mechanism and characteristics by a coaxial swirl injector". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 233, nr 8 (18.04.2019): 1022–38. http://dx.doi.org/10.1177/0957650919844045.

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The overall process and mechanism of the centrifugal pre-film atomization with double swirling flow were studied using the methods of large Eddy simulation and volume of fluid. The atomization process includes a centrifugal jet under the primary swirl and a pre-film atomization under the two-stage counter-rotating swirl at the venturi outlet. The fuel is ejected from the outlet of the centrifugal nozzle and undergoes the transient process of reaching the venturi throat. The breaking mechanism of liquid film in this process is the same as that of the formation mechanism of the mushroom-shaped tip of liquid jet. The numerical simulation results are highly consistent with the experimental results. For the formation and development of the liquid film on the venturi wall, collision and wave action promote the expansion of the liquid film. At the outlet position of the venturi tube, the short wave mode and the two-stage reverse swirling structure play major roles in the fragmentation process of the flake liquid film, which coincides with the flow characteristics given by the experiment. It is found that the spray cone angle increases as the fuel flow rate increases, and the numerical results are basically consistent with the predicted values of the empirical formula under different fuel flow rates. The droplet size distribution showed a Poisson distribution during the atomization of centrifugal jets and pre-film, and the peak position and variation trend of the droplet size distribution at the outlet of the venturi tube were basically consistent with experimental results.

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