Journal articles: 'In-cylinder models'

1

Piiper, Johannes, and Peter Scheid. "Cross-sectional PO2 distributions in Krogh cylinder and solid cylinder models." Respiration Physiology 64, no. 3 (June 1986): 241–51. http://dx.doi.org/10.1016/0034-5687(86)90118-0.

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Žák, Zdeněk, Miloslav Emrich, Michal Takáts, and Jan Macek. "In-Cylinder Heat Transfer Modelling." Journal of Middle European Construction and Design of Cars 14, no. 3 (December 1, 2016): 2–10. http://dx.doi.org/10.1515/mecdc-2016-0009.

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Abstract The goal of the paper is to discuss specific features of the in-cylinder heat transfer calculation based on widely used empirical formulas. The potential of in-house codes compared with commercially available software packages is presented. The principles of user models in the GT-SUITE environment are also explained. The results of calibrated models are briefly discussed.

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Kurbatova, Galina, and Nadezda Ermolaeva. "Analysis of the Cylinder Glaciation Models in Seawater." Applied Mathematics & Information Sciences 11, no. 3 (May 1, 2017): 925–30. http://dx.doi.org/10.18576/amis/110333.

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Sharif, M., and Sobia Sadiq. "Cracking in charged anisotropic cylinder." Modern Physics Letters A 32, no. 18 (April 28, 2017): 1750091. http://dx.doi.org/10.1142/s0217732317500912.

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In this paper, we study the stability of static charged anisotropic cylindrically symmetric compact object through cracking. The Einstein–Maxwell field equations and conservation equation are formulated. We then apply local density perturbation and study the behavior of force distribution function. Finally, the cracking is explored for two models satisfying specific form of Chaplygin equation of state. It is found that these models exhibit cracking and the instability increases as the value of charge parameter is increased.

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Basha, Syed Ameer, and K. Raja Gopal. "In-cylinder fluid flow, turbulence and spray models—A review." Renewable and Sustainable Energy Reviews 13, no. 6-7 (August 2009): 1620–27. http://dx.doi.org/10.1016/j.rser.2008.09.023.

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Kao, Minghui, and John J. Moskwa. "Turbocharged Diesel Engine Modeling for Nonlinear Engine Control and State Estimation." Journal of Dynamic Systems, Measurement, and Control 117, no. 1 (March 1, 1995): 20–30. http://dx.doi.org/10.1115/1.2798519.

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Engine models that are used for nonlinear diesel engine control, state estimation, and model-based diagnostics are presented in this paper. By collecting, modifying, and adding to current available engine modeling techniques, two diesel engine models, a mean torque production model and a cylinder-by-cylinder model, are summarized for use in the formulation of control and state observation algorithms. In the cylinder-by-cylinder model, a time-varying crankshaft inertia model is added to a cylinder pressure generator to simulate engine speed variations due to discrete combustion events. Fuel injection timing and duration are control inputs while varying engine speed, cylinder pressure, and indicated torque are outputs from simulation. These diesel engine models can be used as engine simulators and to design diesel engine controllers and observers.

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Ma, Yong Guang, Ning Ran, and Bing Zheng. "Research of Calculation Models for Exhaust Enthalpy of Steam Turbine." Advanced Materials Research 550-553 (July 2012): 3160–63. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.3160.

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For the low pressure (LP) cylinder of a steam turbine, computation of the exhaust enthalpy is an important part in thermal power generating unit performance monitoring. A new online model for calculating the exhaust enthalpy was proposed aiming at the limitation of existing online calculation model for calculating the enthalpy of steam turbine LP cylinder exhaust steam. This model treats LP cylinder, condenser and corresponding heater as an open system, according to the energy balance equation of this open system, figuring out its exhaust enthalpy. Calculation results of typical steam turbine show that: in a large load change range, the results are close to thermal experimental value, the accuracy is similar to energy balance method.

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Oden, J. T., T. L. Lin, and J. M. Bass. "A Finite Element Analysis of the General Rolling Contact Problem for a Viscoelastic Rubber Cylinder." Tire Science and Technology 16, no. 1 (January 1, 1988): 18–43. http://dx.doi.org/10.2346/1.2148795.

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Abstract Mathematical models of finite deformation of a rolling viscoelastic cylinder in contact with a rough foundation are developed in preparation for a general model for rolling tires. Variational principles and finite element models are derived. Numerical results are obtained for a variety of cases, including that of a pure elastic rubber cylinder, a viscoelastic cylinder, the development of standing waves, and frictional effects.

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Cuper Przybylska, Dominika. "Overview of combustion process models in a cylinder of piston engine." AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, no. 4 (April 30, 2018): 48–52. http://dx.doi.org/10.24136/atest.2018.020.

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The article presents an overview of models used to calculate combustion process parameters in piston engines. One of the applied techniques is modelling based on the mathematical description of physical phenomena. The level of complexity of such a description depends, however, on the purpose of the model, the efficiency of calculations and the possibility of obtaining reliable measurement data. The paper presents various methods of modelling phenomena occurring in the cylinder of a Diesel engine. Presented are assumptions and effects of modelling using models from 0-dimensional and single-zone to complex 3-dimensional models, describing the phenomena of turbulent mass movements using computer fluid mechanics.

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Alam, MM, and MA Momin. "Performance of Existing Maize Shellers in Bangladesh." Progressive Agriculture 20, no. 1-2 (November 5, 2013): 207–20. http://dx.doi.org/10.3329/pa.v20i1-2.16873.

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This study was conducted to identify the technical and economical performance of the existing models of maize sheller in the country and suggest the best maize sheller models for the farmers during 3 September 2006 to 30 March 2007 in the area of Bogra, Rangpur, Dinajpur, Rajshahi and Jessore. Detail field tests were conducted on seven selected maize sheller models of three categories to assess the comparative performance. Three basic designs of maize sheller models were identified through field survey and secondary information. The models were Spike-pinion (SP) type, Spiral rasp-bar cylinder (SBC) type and Parallel rasp-bar cylinder (PBC) type. The technical performances of the selected maize sheller models were evaluated on the basis of throughput capacity, shelling capacity, cylinder loss, separating loss, broken kernel and shelling efficiency. The shelling capacity and efficiency of Binimoy and Sarker spike-pinion (SP) type models were found about 0.45 ton/hr and 93%, respectively. Similarly, the shelling capacities and efficiencies of Farida, Rahman and Uttaran spiral rasp-bar cylinder (SBC) models were ranged between 2.8 to 4.0 ton/hr and 93 to 97%, respectively. Farida parallel rasp-bar (PBC) type maize sheller had shown incredible shelling efficiency of about 99% with almost negligible cylinder (0.25%) and separating (0.25%) losses along with lowest broken kernel (2.5%) percentage. However, the shelling capacity was found comparatively low about 1.9 ton/hr. The shelling costs, benefit-cost ratios and net margins of spiral rasp-bar cylinder models vary between Tk. 91-97/ton, 1.28-1.37 and Tk78-134/hr, respectively. Among the models Farida (SBC) appeared as the most economic one having lowest shelling cost of Tk. 91/ton with the highest benefit-cost ratio of 1.37 and net margin of Tk. 134/hr (determined at a custom-hire rate of Tk. 7 per 40 kg of shelled kernel). Comparative economic uses of the selected maize shellers suggest that the use of hand sheller is beneficial up to an annual use of 13 ton. Whereas, Binimoy (SP) and Sarker (SP) models are economic for annual use between 13 and 30 ton, and Farida (SBC), Rahman (SBC) and Uttaran (SBC) models are economic for shelling over 30 ton per annum. Economic analysis suggest that hand sheller could be beneficial for very small farm holdings, Binimoy (SP) and Sarker (SP) models for small farm holdings and Farida (SBC), Rahman (SBC) and Uttaran (SBC) models for medium to large farm holdings and custom-hire service.DOI: http://dx.doi.org/10.3329/pa.v20i1-2.16873 Progress. Agric. 20(1 & 2): 207 220, 2009

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Zenkour, Ashraf M. "Thermo-diffusion of solid cylinders based upon refined dual-phase-lag models." Multidiscipline Modeling in Materials and Structures 16, no. 6 (April 23, 2020): 1417–34. http://dx.doi.org/10.1108/mmms-12-2019-0213.

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PurposeThe thermo-diffusion analysis of an isotropic cylinder under thermal flux and chemical potential impacts has been discussed. Improvements of Green and Naghdi generalized thermoelasticity theory have been proposed.Design/methodology/approachSome models with and without energy dissipation have been presented as well as the simple forms of Green–Naghdi (G–N) theories. These novel multi- and single-/dual-phase-lag models are presented to investigate the thermo-diffusion of the solid cylinder. The closed-form solution of thermo-diffusion governing equations of solid cylinder has been obtained to deduce all field variables.FindingsA comparison study between the simple G–N II and III models and their improved models has been presented. The validations of outcomes are acceptable and so benchmarks are reported to help other investigators in their future comparisons.Originality/valueThe modified Green and Naghdi theories of types II and III are presented to get novel and accurate models of single- and dual-phase-lag of multiterms. The heat of mass diffusion equation as well as the constitutive equations for the stresses and chemical potential of a solid cylinder is added to the present formulation. The system of three differential coupled equations is solved, and all field variables are obtained for the thermal diffusion of the solid cylinder. Some validation examples and applications are presented to compare the simple and modified Green and Naghdi theories of types II and III. Sample plots are illustrated along the radial direction of the solid cylinder. Some results are tabulated to serve as benchmark results for future comparisons with other investigators. The reported and illustrated results show that the simple G–N II and III models yield the largest values of all field quantities. The single-phase-lag models give the smallest values. However, the dual-phase-lag model yields results that are intermediate between those of the simple and single-phase-lag G–N models.

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12

Bai, Xu, Xiao Tian Wang, Li Ping Sun, Guo Dong Hu, and Jin Hua Li. "Experimental Investigation of the Edge Stress of Sphere-Cylinder Combined Shell." Applied Mechanics and Materials 268-270 (December 2012): 1153–57. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.1153.

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Sphere-cylinder combined shell is one of the main pressure hull forms of submersible. This paper analyzes on edge stress of sphere-cylinder combined shell under external hydrostatic pressure. The edge models of cylindrical and spherical parts of combined shells are established by moment analysis and deformation compatibility. In the experiment, a ring-stiffened cylinder with hemispherical end is designed to verify edge models. The results of stress analysis are discussed in the paper.

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13

Lake, Matthew, Haiping He, Armin W. Troesch, Marc Perlin, and Krish P. Thiagarajan. "Hydrodynamic Coefficient Estimation for TLP and Spar Structures." Journal of Offshore Mechanics and Arctic Engineering 122, no. 2 (December 17, 1999): 118–24. http://dx.doi.org/10.1115/1.533733.

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Research papers at previous OMAE conferences by Thiagarajan and Troesch 45 described forced oscillation model tests using a 0.45-m-dia cylinder and a 0.6-m-disk appended to the cylinder base for drag augmentation. Scaling laws were proposed based on a component scaling concept for extrapolation of full-scale added mass and damping coefficients. The present work further verifies the scaling methodology by presenting and discussing results on smaller models—cylinder and disk of diameters 0.15 m and 0.19 m, respectively. The dimensions of the smaller models are typical of more complex offshore platform models tested in scale 1:50 to 1:75 design sea states. The hydrodynamic coefficients of the cylinder and of the disk are estimated individually, and component-scaling methodology is examined. Physics-based arguments for the differences in force coefficients of the configurations are discussed: flow around the cylinder, flow around the disk, and flow around the composite structure. The analysis results from force measurements and flow visualization conducted during forced oscillation experiments. Further, difficulties in maintaining accuracy with the smaller models are examined. [S0892-7219(00)00202-8]

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Wang, Hong Bo, Ying Xue Yao, and Yong Zhan Zhou. "Research on Measurement of Viscosity Based on Cylinder Rotation." Applied Mechanics and Materials 16-19 (October 2009): 1030–32. http://dx.doi.org/10.4028/www.scientific.net/amm.16-19.1030.

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Value of viscosity of liquid at an arbitrary velocity is important in many manufacturing processes, method of rotation is used commonly to measure it at a scheduled velocity, but it is not convenient to measure it at an arbitrary velocity. A method based on cylinder rotation is presented in the paper and it is used to measure it at an arbitrary velocity. Derivation of mathematical models is executed and a simulation is carried in Matlab. Results show that the velocity of the cylinder in the liquid attenuates by exponential law and it is in accordance with mathematical models. Error analysis indicates that that the generation of them mainly results from unsuited velocity of cylinder, slippage between the cylinder and the liquid and misalignment between the cylinder and the cup.

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Tran, Xuan Bo, Van Lai Nguyen, and Khanh Duong Tran. "Effects of friction models on simulation of pneumatic cylinder." Mechanical Sciences 10, no. 2 (October 30, 2019): 517–28. http://dx.doi.org/10.5194/ms-10-517-2019.

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Abstract. This study examines effects of three friction models: a steady-state friction model (SS model), the LuGre model (LG model), and the revised LuGre model (RLG model) on the motion simulation accuracy of a pneumatic cylinder. An experimental set-up of an electro-pneumatic servo system is built, and characteristics of the piston position, the pressures in the two-cylinder chambers and the friction force are measured and calculated under different control inputs to the proportional flow control valves. Mathematical model of the electro-pneumatic servo system is derived, and simulations are carried out under the same conditions as the experiments. Comparisons between measured characteristics and simulated ones show that the RLG model can give the best agreement among the three friction models while the LG model can only simulate partly the stick-slip motion of the piston at low velocities. The comparison results also show that the SS model used in this study is unable to simulate the stick-slip motion as well as creates much oscillations in the friction force characteristics at low velocities.

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Lai, Qiwei, Liang Liang, Jing Li, Shijing Wu, and Jun Liu. "Modeling and Analysis on Cushion Characteristics of Fast and High-Flow-Rate Hydraulic Cylinder." Mathematical Problems in Engineering 2016 (2016): 1–17. http://dx.doi.org/10.1155/2016/2639480.

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As an indispensable actuator, the hydraulic cylinder has widespread industrial applications in mechanical engineering. The cushion characteristics of hydraulic cylinder directly affect its performance and reliability, especially the one utilized in hydraulic system with fast response, high flow rate, and instantaneous super power. In order to analyze the cushion characteristics, three different simulation models are established. Furthermore, experiments concerning the pressure characteristics of hydraulic cylinder are accomplished to verify the validation of simulation models. It was found that the integrated simulation model had the highest precision and CFD model showed better pattern of cushion process compared with other models. On the basis of the integrated simulation model, plunger structure and key structural parameters were studied in detail with optimal schemes given. The conical structure, proper design of the diameter of cushion hole, and length of plunger turned out to be effective in promoting the cushion performance. The proposed simulation models and research of cushion structure have scientific and engineering value to promote the innovative development of hydraulic cylinder.

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Madeira, Rafael A., and Dan Sui. "Study on separation factor models for well anti-collision analysis." Journal of Petroleum Exploration and Production Technology 11, no. 9 (July 20, 2021): 3463–77. http://dx.doi.org/10.1007/s13202-021-01235-w.

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AbstractAnti-collision analysis has been becoming even more important in the past few years with the increasing amount of wells drilled in highly congested fields. The separation factor (SF) is a critical safety parameter to avoid wellbore collisions, where the pedal curve method (PCM) is the commonly used way for the SF calculation. However, such method may be conservative in many situations and possibly triggers an unnecessary early stop drilling due to its conservation. In this study, our work aims to evaluate and compare the different types of the SF models. In addition, an alternative and supplement method of the PCM, called as elliptic cylinder of uncertainty (ECoU) method, is proposed. The radius of the ECoU considers the distance of the intersecting points of the center-to-center line and the cylinder surfaces of both reference and offset wells. By introducing the cylinder surfaces into the SF calculation, it could extend the collision avoidance along the whole well path to reduce multiple-points collision possibility. The findings in the study help us for better understanding of the SF analysis and also show that using the ECoU indication has a great potential in fields applications as a viable method to keep the drilling operations’ safety.

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Natarajan, R., G. E. O. Widera, and P. Afshari. "A Finite Element Model to Analyze Cylinder-Cylinder Intersections." Journal of Pressure Vessel Technology 109, no. 4 (November 1, 1987): 411–20. http://dx.doi.org/10.1115/1.3264924.

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A finite element model is proposed to study the stresses in the neighborhood of a cylinder-cylinder intersection. In particular, diameter ratios greater than 0.5 are focused upon since little information is available in the ASME Boiler and Pressure Vessel Code or in the literature about the stress concentration for these geometries. The aim of the present work is to validate such a model for internal pressure loading. To accomplish this, various parametric finite element studies were conducted. The selected model is then validated by applying it to various available cylinder intersection models and comparing the results. The finite element results are further compared with a solution obtained using a shell theory.

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Algieri, Angelo, Sergio Bova, Carmine De Bartolo, and Alessandra Nigro. "Numerical and Experimental Analysis of the Intake Flow in a High Performance Four-Stroke Motorcycle Engine: Influence of the Two-Equation Turbulence Models." Journal of Engineering for Gas Turbines and Power 129, no. 4 (January 24, 2007): 1095–105. http://dx.doi.org/10.1115/1.2719265.

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An experimental and numerical analysis of the intake system of a production high performance four-stroke motorcycle engine was carried out. The aim of the work was to characterize the fluid dynamic behavior of the engine during the intake phase and to evaluate the capability of the most commonly used two-equation turbulence models to reproduce the in-cylinder flow field for a very complex engine head. Pressure and mass flow rates were measured on a steady-flow rig. Furthermore, velocity measurements were obtained within the combustion chamber using laser Doppler anemometry (LDA). The experimental data were compared to the numerical results using four two-equation turbulence models (standard k-ε, realizable k-ε, Wilcox k-ω, and SST k-ω models). All the investigated turbulence models well predicted the global performances of the intake system and the mean flow structure inside the cylinder. Some differences between measurements and computations were found close to the cylinder head while an improving agreement was evident moving away from the engine head. Furthermore, the Wilcox k-ω model permitted the flow field inside the combustion chamber of the engine to be reproduced and the overall angular momentum of the flux with respect to the cylinder axis to be quantified more properly.

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Zydek, S., D. Casper, R. Isermann, and A. Weber. "Determining the Initial In-Cylinder Gas State Based on Semi-Physical Models." IFAC-PapersOnLine 49, no. 11 (2016): 454–60. http://dx.doi.org/10.1016/j.ifacol.2016.08.067.

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Sundaravadivelu, R., R. Harps, and O. Mahrenholtz. "Twin Floating Connected Models in Regular Beam Waves." Journal of Offshore Mechanics and Arctic Engineering 114, no. 4 (November 1, 1992): 242–49. http://dx.doi.org/10.1115/1.2919976.

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This paper presents the studies carried out on twin floating models connected alongside with hinge connection in regular beam waves of different frequencies in a wave flume. The heave, roll and sway, normalized with the wave amplitude are reported for a single box, a single half-cylinder, twin boxes and twin half-cylinders. The effect of separation distance and stiffness of the connection on the response of the twin models are also reported.

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Kao, Minghui, and John J. Moskwa. "Nonlinear Diesel Engine Control and Cylinder Pressure Observation." Journal of Dynamic Systems, Measurement, and Control 117, no. 2 (June 1, 1995): 183–92. http://dx.doi.org/10.1115/1.2835178.

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This paper presents novel approaches to nonlinear engine fuel controller and cylinder pressure observer designs based on mean torque production and cylinder-by-cylinder models. Sliding mode controllers and sliding mode observers have shown good robustness and high tracking performance. Accordingly, they are selected in this study to fulfill demanding engine electronic control and onboard diagnostics requirements.

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23

Magome, Kazuyoshi, Naoyuki Morishige, Akifumi Ueno, Taka-Aki Matsui, and Eiichi Uchio. "Prediction of cycloplegic refraction for noninvasive screening of children for refractive error." PLOS ONE 16, no. 3 (March 15, 2021): e0248494. http://dx.doi.org/10.1371/journal.pone.0248494.

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Detection of refractive error in children is crucial to avoid amblyopia and its impact on quality of life. We here performed a retrospective study in order to develop prediction models for spherical and cylinder refraction in children. The enrolled 1221 eyes of 617 children were divided into three groups: the development group (710 eyes of 359 children), the validation group (385 eyes of 194 children), and the comparison group (126 eyes of 64 children). We determined noncycloplegic and cycloplegic refraction values by autorefractometry. In addition, several noncycloplegic parameters were assessed with the use of ocular biometry. On the basis of the information obtained from the development group, we developed prediction models for cycloplegic spherical and cylinder refraction in children with the use of stepwise multiple regression analysis. The prediction formulas were validated by their application to the validation group. The similarity of noncycloplegic and predicted refraction to cycloplegic refraction in individual eyes was evaluated in the comparison group. Application of the developed prediction models for spherical and cylinder refraction to the validation group revealed that predicted refraction was significantly correlated with measured values for cycloplegic spherical refraction (R = 0.961, P < 0.001) or cylinder refraction (R = 0.894, P < 0.001). Comparison of noncycloplegic, cycloplegic, and predicted refraction in the comparison group revealed that cycloplegic spherical refraction did not differ significantly from predicted refraction but was significantly different from noncycloplegic refraction, whereas cycloplegic cylinder refraction did not differ significantly from predicted or noncycloplegic values. Our prediction models based on ocular biometry provide estimates of refraction in children similar to measured cycloplegic spherical and cylinder refraction values without the application of cycloplegic eyedrops.

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Daud, Yusof, Margaret Lucas, and Khairur Rijal Jamaludin. "Finite Element Modelling in Ultrasonic Sheet Metal Forming." Advanced Materials Research 445 (January 2012): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amr.445.3.

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Finite element (FE) model of die necking process of an aluminium hollow thin cylinder has been developed. The input parameters of material properties and coefficient of friction, µ for the model have been deducted from our previous experimental study. Later the models have been validated against experimental data as reported in the previous studies. For the die necking process, the FE model has successfully to predict how much the original diameter of the aluminium hollow cylinder can be maximised necked with and without applying ultrasonic vibration. FE models showed that the application of ultrasonic vibration during the necking process has reduced buckling of the cylinder body if compared to the necking process without ultrasonic. The benefit of applying ultrasonic vibration in sheet metal forming process has been related to the reduction of interface friction between die and specimen.

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Singh, Sahjendra N., James H. Myatt, Gregory A. Addington, Siva Banda, and James K. Hall. "Optimal Feedback Control of Vortex Shedding Using Proper Orthogonal Decomposition Models." Journal of Fluids Engineering 123, no. 3 (May 1, 2001): 612–18. http://dx.doi.org/10.1115/1.1385513.

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This paper treats the question of control of two-dimensional incompressible, unsteady wake flow behind a circular cylinder at Reynolds number Re=100. Two finite-dimensional lower order models based on proper orthogonal decomposition (POD) are considered for the control system design. Control action is achieved via cylinder rotation. Linear optimal control theory is used for obtaining stabilizing feedback control systems. An expression for the region of stability of the system is derived. Simulation results for 18-mode POD models obtained using the control function and penalty methods are presented. These results show that in the closed-loop system mode amplitudes asymptotically converge to the chosen equilibrium state for each flow model for large perturbations in the initial states.

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Lennon, R. F. "The Effects of Cold Forming and Welding Residual Stress States on the Buckling Resistance of Orthogonally Stiffened Cylinders." Applied Mechanics and Materials 5-6 (October 2006): 509–18. http://dx.doi.org/10.4028/www.scientific.net/amm.5-6.509.

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The buckling resistance of orthogonally stiffened cylinders is investigated for elastic critical buckling and non-linear elasto-plastic buckling tests. The effects of residual stresses arising from cold forming the cylinder and welding frame components are considered in the analysis of two stiffened cylinder models with similar material weights and different geometric spacings. A static axial load is applied to the models to represent loading from the supported structure followed by a non-linear elasto-plastic buckling step representing a wave loading combined with hydrostatic pressure, producing large displacement compartment buckling. Residual stress is shown to cause a reduction in buckling resistance of approximately 25% in the stiffened cylinder segments.

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Wang, Qi, Xiongwen Zhao, Shu Li, Mengjun Wang, Shaohui Sun, and Wei Hong. "Attenuation by a Human Body and Trees as well as Material Penetration Loss in 26 and 39 GHz Millimeter Wave Bands." International Journal of Antennas and Propagation 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/2961090.

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This paper investigates the attenuation by a human body and trees as well as material penetration loss at 26 and 39 GHz by measurements and theoretical modeling work. The measurements were carried out at a large restaurant and a university campus by using a time domain channel sounder. Meanwhile, the knife-edge (KE) model and one-cylinder and two-cylinder models based on uniform theory of diffraction (UTD) are applied to model the shape of a human body and predict its attenuation in theory. The ITU (International Telecommunication Union) and its modified models are used to predict the attenuation by trees. The results show that the upper bound of the KE model is better to predict the attenuation by a human body compared with UTD one-cylinder and two-cylinder models at both 26 and 39 GHz. ITU model overestimates the attenuation by willow trees, and a modified attenuation model by trees is proposed based on our measurements at 26 GHz. Penetration loss for materials such as wood and glass with different types and thicknesses is measured as well. The measurement and modeling results in this paper are significant and necessary for simulation and planning of fifth-generation (5G) mm-wave radio systems in ITU recommended frequency bands at 26 and 39 GHz.

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Thothadri, M., and F. C. Moon. "An Investigation of Nonlinear Models for a Cylinder Row in a Cross Flow." Journal of Pressure Vessel Technology 121, no. 2 (May 1, 1999): 133–41. http://dx.doi.org/10.1115/1.2883676.

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An array of elastically supported cylinders placed in a uniform fluid flow perpendicular to their long axis has been known to perform large-amplitude oscillations when the flow velocity is increased past a critical value. Experimental investigations have shown that the linear stability of the cylinder row is lost through a subcritical Hopf bifurcation resulting in the now well-known hysteresis regime. In this study, we investigate the nonlinearities in the dynamics of the fluid-elastic system, with particular emphasis on capturing the global bifurcation behavior of the cylinders by proposing two nonlinear models. Although the proposed nonlinear models are mostly arbitrary, when appropriate choices are made for the unknown coefficients in the models, based on the theory of center manifolds and normal forms, the predictions of the models, based on the theory of center manifolds and normal forms, the predictions of the models are reasonable. While one of the models captures the experimental bifurcation diagram qualitatively, the other nonlinear model exhibits secondary bifurcation, resulting in coexisting periodic and quasi-periodic solutions.

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Havran, R. L. "3500 SI Engine Application Flexibility." Journal of Engineering for Gas Turbines and Power 113, no. 3 (July 1, 1991): 340–44. http://dx.doi.org/10.1115/1.2906235.

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The 3500 Spark-Ignited Engine is a 170 mm bore by 190 mm stroke family including 8, 12, and 16-cylinder models rated at 54 bkW per cylinder. Initial production included low-emission versions of the 12 and 16 cylinder engines in 1986. This paper describes basic combustion and attachment developments that have broadened the product offering for improved performance in more varied fuel and high-temperature cogeneration applications.

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Okajima, Atsushi, Takashi Kosugi, and Akira Nakamura. "Flow-Induced In-Line Oscillation of a Circular Cylinder in a Water Tunnel." Journal of Pressure Vessel Technology 124, no. 1 (June 22, 2001): 89–96. http://dx.doi.org/10.1115/1.1430670.

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Flow-induced in-line oscillation of a circular cylinder has been experimentally studied by free-oscillation tests in a water tunnel. Response amplitudes of a circular cylinder have been measured for determining the values of the reduced mass-damping parameter of less than 1.0. In the free-oscillation tests, the cylinder models were spring-mounted so as to oscillate as a two-dimensional rigid cylinder in the water tunnel. Two types of excitation phenomena appear at approximately half of the resonance flow velocity. The response amplitudes are sensitive to the reduced mass-damping parameter during the in-line oscillation of the first excitation region with a symmetric vortex street, and the alternate vortices are periodically shed, locking-in with the vibration of the cylinder in the second excitation region. A hysteresis phenomenon is observed to appear in the in-line oscillation of the latter region. A cantilevered circular cylinder with a finite length aspect ratio of 10 was tested for fluid-elastic characteristics of the cylinder, and these characteristics are found to be quite different from those of the two-dimensional cylinder, having only one wide velocity region of excitation. The results of this study are providing important supporting data for the recent publication “Guideline for Evaluation of Flow-Induced Vibration of a Cylindrical Structure in a Pipe,” by the Japan Society of Mechanical Engineers, Standard JSME S012-1998.

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Krill, Malte, and Deborah L. Thurston. "Remanufacturing: Impacts of Sacrificial Cylinder Liners." Journal of Manufacturing Science and Engineering 127, no. 3 (August 11, 2004): 687–97. http://dx.doi.org/10.1115/1.1961946.

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Remanufacturing offers the potential for simultaneously recovering the economic value of manufactured components and improving the environment. Some design features make remanufacturing less expensive and/or increase the proportion of components that can be remanufactured. For example, sacrificial components can be used to protect key parts from wear. However, trade-offs are sometimes involved, and product designers need tools to support design for remanufacturing. This paper presents models for estimating the costs and environmental impacts of employing sacrificial components (cylinder liners) in engine blocks. These models are incorporated into a spreadsheet-based design decision tool. Three illustrative examples demonstrate that (1) remanufacturing lowers overall costs when two life cycles are considered, (2) sacrificial cylinder liners should be employed for small (2 L) engines, and their superiority increases with multiple remanufacturing cycles, and (3) for large engines (5.3 L) using cylinder liners is equally preferred to not using them, with respect to both overall cost and environmental impacts.

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Surzhikov, S. T. "An analysis of ionization kinetics models in a hypersonic flow past a cylinder." Russian Journal of Physical Chemistry B 4, no. 4 (August 2010): 613–26. http://dx.doi.org/10.1134/s1990793110040123.

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Dong, Y., and J. A. Richards. "Studies of the cylinder-ground double bounce scattering mechanism in forest backscatter models." IEEE Transactions on Geoscience and Remote Sensing 33, no. 1 (1995): 229–31. http://dx.doi.org/10.1109/36.368203.

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Tzou, Gow Yi, Wen T. Chien, Ming Nan Huang, and Dong Lin Cai. "Slab Method Analysis and FEM Simulation on Rotating Compression Forming of Cylinder Considering Coulomb Friction." Materials Science Forum 561-565 (October 2007): 73–76. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.73.

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An investigation into the compression forming of cylinder using the commercial code SUPERFORM is developed. The cylinder billet compressed between the upper and lower dies is meshed by a quadrangle elastic-plastic element. The numerical simulation based on the FEM also compares with the slab method established by us. In the slab method analysis, the stress distributions are estimated by considering the coulomb friction between the dies and the cylinder. Throughout this study, the effects of frictional coefficient, rotating angular speed, reduction and aspect ratio etc upon the compression force, the effective stress and the effective strain, and velocity field are discussed systematically. For verifying the validity of two models, comparisons of compression forces based both modes are carried out to prove the feasibility of both models.

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Li, Song Bai, and Yi Lun Liu. "Spiral Flow Capability Research in the Rotary Cylinder." Applied Mechanics and Materials 103 (September 2011): 209–13. http://dx.doi.org/10.4028/www.scientific.net/amm.103.209.

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In order to obtain the lubricating capabilityof screw rotary cylinder, its structural design and operation principle were introduced. Seven screw pairs with different radial clearance were designed. The models were built by Pro/E. Structure mesh was generated by using Gambit. Based on laminar flow model and SIMPLE algorithm, the interior flow field in different radial clearances and the same radial clearance at different inlet pressure were numerically simulated and analyzed with Fluent. The relationship of loading force, stiffness, maximum temperature, flow rate and radial clearance were obtained. Simulation results show that the performance of oil lubricated screw pair is the best at the radial clearance of 0.10 mm. At the same radial clearance, when back pressure is constant, with inlet pressure increasing, loading force, stiffness, flow rate and maximum temperature increase completely.

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Xiao, Jin Sheng, Chun Xiao Liu, Wen Hua Zhao, and Wei Biao Fu. "Analysis of Heat Transfer and Thermal Stress in Thermal and Environmental Barrier Coatings." Key Engineering Materials 336-338 (April 2007): 1784–87. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.1784.

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A kind of gradient thermal and environmental barrier coating applied in internal combustion engine is brought forward to improve its reliability, emission and efficiency. The multi-layer plate and cylinder models are established for the simulations of heat transfer and thermal stress in the coatings. Both the theoretical and the numerical analysis with multi-layer cylinder model with coating inside are carried out and compared. The results show good agreement.

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37

Tee, J. W., S. H. Hamdan, and W. W. F. Chong. "Predictive tool for frictional performance of piston ring-pack/liner conjunction." Journal of Mechanical Engineering and Sciences 13, no. 3 (September 27, 2019): 5513–27. http://dx.doi.org/10.15282/jmes.13.3.2019.19.0445.

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Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

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Mulyadi, Cecep Deni. "ANALYSIS OF IMPROVEMENT CAUSING DAMAGE TO CYLINDER LINERS AND PISTON RODS IN VEHICLE MODELS (F65 # -3SZ)." ENSAINS JOURNAL 2, no. 2 (May 14, 2019): 85. http://dx.doi.org/10.31848/ensains.v2i2.241.

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Abstract: Cases that occur complaining about the engine on the vehicle is abnormal, both in idling and high rpm, when the initial inspection is carried out, there appear to be abnormal symptoms on the vehicle's engine.So it needs repairs to the vehicle where there is a problem in the vehicle, which complains about the abnormal state of the engine both the state of idling or middle and high rpm.After doing repairs, the problems that occur occur. The water hammer is caused by a cowl top seal that has no locking clip and water filter assembly. As a result of the water hammer being produced, there is damage to the components inside the cylinder block, namely the cylinder liner and piston rod.Keywords: Abnormal, When Idling, High Rpm

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Zhang, Weiwei, Xintao Li, Zhengyin Ye, and Yuewen Jiang. "Mechanism of frequency lock-in in vortex-induced vibrations at low Reynolds numbers." Journal of Fluid Mechanics 783 (October 14, 2015): 72–102. http://dx.doi.org/10.1017/jfm.2015.548.

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In this study, a CFD-based linear dynamics model combined with the direct Computational Fluid Dynamics/Computational Structural Dynamics (CFD/CSD) simulation method is utilized to study the physical mechanisms underlying frequency lock-in in vortex-induced vibrations (VIVs). An identification method is employed to construct the reduced-order models (ROMs) of unsteady aerodynamics for the incompressible flow past a vibrating cylinder at low Reynolds numbers ($Re$). Reduced-order-model-based fluid–structure interaction models for VIV are also constructed by coupling ROMs and structural motion equations. The effects of the natural frequency of the cylinder, mass ratio and structural damping coefficient on the dynamics of the coupled system at $Re=60$ are investigated. The results show that the frequency lock-in phenomenon at low Reynolds numbers can be divided into two patterns according to different induced mechanisms. The two patterns are ‘resonance-induced lock-in’ and ‘flutter-induced lock-in’. When the natural frequency of the cylinder is in the vicinity of the eigenfrequency of the uncoupled wake mode (WM), only the WM is unstable. The dynamics of the coupled system is dominated by resonance. Meanwhile, for relatively high natural frequencies (i.e. greater than the eigenfrequency of the uncoupled WM), the structure mode becomes unstable, and the coupling between the two unstable modes eventually leads to flutter. Flutter is the root cause of frequency lock-in and the higher vibration amplitude of the cylinder than that of the resonance region. This result provides evidence for the finding of De Langre (J. Fluids Struct., vol. 22, 2006, pp. 783–791) that frequency lock-in is caused by coupled-mode flutter. The linear model exactly predicts the onset reduced velocity of frequency lock-in compared with that of direct numerical simulations. In addition, the transition frequency predicted by the linear model is in close coincidence with the amplitude of the lift coefficient of a fixed cylinder for high mass ratios. Therefore, it confirms that linear models can capture a significant part of the inherent physics of the frequency lock-in phenomenon.

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Heller, William T. "ELLSTAT: shape modeling for solution small-angle scattering of proteins and protein complexes with automated statistical characterization." Journal of Applied Crystallography 39, no. 5 (September 12, 2006): 671–75. http://dx.doi.org/10.1107/s0021889806029591.

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A method is presented for constructing one- and two-ellipsoid, core-shell-ellipsoid, cylinder and ellipsoid-plus-cylinder models from small-angle X-ray and neutron scattering data that calculates statistics on the resulting structural parameters. The method, implemented in the softwareELLSTAT, is capable of simultaneously fitting against several data sets and calculates averages, standard deviations and coefficients of linear correlation between the structural parameters of the resulting models. In this way, an improved understanding of the extent of the variability in and the interdependency between the model parameters that fit the input scattering data is developed, thereby providing a measure of the uniqueness of the models.

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Sun, Jianmin, and Qing Mei Yang. "Wear Mechanisms Approach to Ni-P Electroless Plating Applied to Hardening Engine Cylinder." Advanced Materials Research 189-193 (February 2011): 1918–21. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.1918.

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For practical operation conditions of engine cylinder, piston speed and lateral pressure to cylinder wall are determined as experimental factors. According to load and speed on 1mm~8mm below top dead center of cylinder in expansion stroke, the ranges of experimental parameters are chosen. Based on the quadratic regression rotation combination method, wear resistance experiment of hardening material is designed. The wear mathematic models of Ni-P electroless plating is established, and three-dimensional curved surfaces for load-speed-wearing value are drawn. The results show that the Ni-P electroless plating can increase relative wear resistance of cylinder by 5 times. By analysis of wear mechanisms of hardening material and wear resistance, the material is perfect for hardening engine cylinder wall.

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Cai, Shibo, Shunlei Wu, and Guanjun Bao. "Cylinder Position Servo Control Based on Fuzzy PID." Journal of Applied Mathematics 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/375483.

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The arbitrary position control of cylinder has always been the hard challenge in pneumatic system. We try to develop a cylinder position servo control method by combining fuzzy PID with the theoretical model of the proportional valve-controlled cylinder system. The pressure differential equation of cylinder, pressure-flow equation of proportional valve, and moment equilibrium equation of cylinder are established. And the mathematical models of the cylinder driving system are linearized. Then fuzzy PID control algorithm is designed for the cylinder position control, including the detail analysis of fuzzy variables and domain, fuzzy logic rules, and defuzzification. The stability of the proposed fuzzy PID controller is theoretically proved according to the small gain theorem. Experiments for targets position of 250 mm, 300 mm, and 350 mm were done and the results showed that the absolute error of the position control is less than 0.25 mm. And comparative experiment between fuzzy PID and classical PID verified the advantage of the proposed algorithm.

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43

Wilson, J. F., and J. C. Tinsley. "Vortex Load Reduction: Experiments in Optimal Helical Strake Geometry for Rigid Cylinders." Journal of Energy Resources Technology 111, no. 2 (June 1, 1989): 72–76. http://dx.doi.org/10.1115/1.3231408.

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Vortex-induced lift loads and their energy spectra were measured on laboratory-scale models of isolated, rigid, right circular cylinders subjected to steady, transverse currents. The control cylinder was smooth and the others were fitted with right-handed or left-handed, constant angle helical strakes that protruded one-tenth the cylinder diameter. For Reynolds numbers of the order of 104, the results clearly show that, compared with the smooth cylinder counterpart, the geometry that most effectively reduces both the lift coefficient and also the peaks of the lift load energy spectra in the low frequency band is three evenly spaced strakes at a 60-deg angle with the cylinder’s transverse axis.

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Chaplin, J. R., K. Subbiah, and M. Irani. "Loading on a Vertical Cylinder in Multidirectional Waves." Journal of Offshore Mechanics and Arctic Engineering 117, no. 3 (August 1, 1995): 151–58. http://dx.doi.org/10.1115/1.2827083.

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This paper presents laboratory measurements of local and total loading on an isolated vertical cylinder in irregular unidirectional and multidirectional waves. Maximum Keulegan-Carpenter numbers in individual waves were about 16, and maximum Reynolds numbers about 3 × 104. It is shown that in these conditions, existing theoretical and numerical models underestimate the reduction in loading on a cylinder due to wave spreading. Besides the changes that are predicted when Morison’s equation is used with constant coefficients, there are hydrodynamic influences that contribute further force reductions. Comparisons with Dean’s (1977) hybrid approach suggest that in the present conditions these reductions are in the region of 3 and 6 percent for a spreading function cos2s θ, with s = 8 and s = 2, respectively. Larger reductions can be expected at higher Keulegan-Carpenter numbers, though scale effects are likely to become more important in the drag-dominated regime.

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45

Miran, Sajjad, and Chang Hyun Sohn. "Numerical study of the rounded corners effect on flow past a square cylinder." International Journal of Numerical Methods for Heat & Fluid Flow 25, no. 4 (May 5, 2015): 686–702. http://dx.doi.org/10.1108/hff-12-2013-0339.

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Purpose – The purpose of this paper is to numerically investigate the influence of corner radius on flow past a square cylinder at a Reynolds number 500. Design/methodology/approach – Six models were studied, for R/D=0 (square cylinder), 0.1, 0.2, 0.3, 0.4, and 0.5 (circular cylinder), where R is the corner radius and D is the characteristic dimension of the body. The transient two-dimensional (2D) laminar and large eddy simulations (LES) models were employed using finite volume code. The Strouhal number, mean drag coefficient (CD), and root mean square (RMS) value of lift coefficient (CL,RMS), for different R/D values, were computed and compared with experimental and other numerical results. Findings – The computational results showed good agreement with previously published results for a Reynolds number, Re=500. It was found that the corner effect on a square cylinder greatly influences the flow characteristics around the cylinder. Results indicate that, as the corner radius ratio, R/D, increases, the Strouhal number increases rapidly for R/D=0-0.2, and then gradually rises between R/D=0.2 and 0.5. The minimum values of the mean drag coefficient and the RMS value of lift coefficient were found around R/D=0.2, which is verified by the time averaged streamwise velocity deficit profile. Originality/value – On the basis of the numerical results, it is concluded that rounded corners on a square cylinder are useful in reducing the drag and lift forces generated behind a cylinder. Finally, it is suggested that with a rounded corner ratio of around R/D=0.2, the drag and oscillation of the cylinder can be greatly reduced, as compared to circular and square cylinders.

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46

Zhan, Yan Jia, Tao Wang, and Bo Wang. "Study on Friction Characteristics of Energizing Pneumatic Cylinders." Advanced Materials Research 904 (March 2014): 306–10. http://dx.doi.org/10.4028/www.scientific.net/amr.904.306.

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As a special kind of pneumatic cylinder, energizing pneumatic cylinder can increase the output force without changing diameter by a series of two or more piston on a piston rod. Since the friction characteristics of pneumatic cylinders is one of the most important factors affecting the nonlinearity, a new experimental apparatus is designed to have an in-depth study, base on exhaust throttle. The friction of energizing pneumatic cylinder was tested under different working pressure and velocity to ascertain the parameters of stribeck model. The results show that friction model of the energizing pneumatic cylinder can be the superposition of the models of each piston.

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Wang, Zhikai, Xiongliang Yao, Nana Yang, and Zhenhuan Xu. "Simulation of Fluid and Structure Interface with Immersed Boundary–Lattice Boltzmann Method Involving Turbulence Models." Mathematical Problems in Engineering 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/4072758.

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The multiple-relaxation-time (MRT) version of the immersed boundary–lattice Boltzmann (IB-LB) method is developed to simulate fluid-structure interfaces. The innovations include the implicit velocity correction to ensure no-slip boundary conditions and the incorporated Smagorinsky’s algebraic eddy viscosity for simulating turbulent flows. Both straight and curved interfaces are investigated. The streamlines penetration can be well prevented, which means the no-slip boundary condition can be guaranteed. Due to the existence of two coordinate systems: the Lagrangian coordinate system and the Eulerian coordinate system, the velocity and force properties on the structure can be easily calculated. Several benchmark simulation cases are carried out to verify the correctness of the model, including flow around circular cylinder at Re = 20, 150, and 3900 and flow around square cylinder at Re = 150 and 1000. The results agree well with previous studies, especially in the events of lower Reynolds numbers. Due to the three-dimensional turbulence vortex effects, the discrepancy increases are associated with higher Reynolds numbers. In addition, the effect of rotating velocity on the interaction process of the square cylinder in flows is researched, coupled with the capability of dealing with the moving boundaries.

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48

Toman, Rastislav, and Jan Macek. "Evaluation of the Predictive Capabilities of a Phenomenological Combustion Model for Natural Gas SI Engine." Journal of Middle European Construction and Design of Cars 15, no. 2 (December 20, 2017): 37–48. http://dx.doi.org/10.1515/mecdc-2017-0007.

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Abstract The current study evaluates the predictive capabilities of a new phenomenological combustion model, available as a part of the GT-Suite software package. It is comprised of two main sub-models: 0D model of in-cylinder flow and turbulence, and turbulent SI combustion model. The 0D in-cylinder flow model (EngCylFlow) uses a combined K-k-ε kinetic energy cascade approach to predict the evolution of the in-cylinder charge motion and turbulence, where K and k are the mean and turbulent kinetic energies, and ε is the turbulent dissipation rate. The subsequent turbulent combustion model (EngCylCombSITurb) gives the in-cylinder burn rate; based on the calculation of flame speeds and flame kernel development. This phenomenological approach reduces significantly the overall computational effort compared to the 3D-CFD, thus allowing the computation of full engine operating map and the vehicle driving cycles. Model was calibrated using a full map measurement from a turbocharged natural gas SI engine, with swirl intake ports. Sensitivity studies on different calibration methods, and laminar flame speed sub-models were conducted. Validation process for both the calibration and sensitivity studies was concerning the in-cylinder pressure traces and burn rates for several engine operation points achieving good overall results.

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Kislev, T., G. Marom, L. Berglund, R. Joffe, J. A. Nairn, and H. D. Wagner. "On the Nature of Opaque Cylindrical Regions Formed at Fibre Break Sites in a Fragmentation Test." Advanced Composites Letters 11, no. 1 (January 2002): 096369350201100. http://dx.doi.org/10.1177/096369350201100101.

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When a single-fibre composite test is performed to obtain information about the interfacial adhesion in a composite, a gradual strain increase often causes an opaque (black) cylinder to nucleate at, and grow from, the fibre failure sites. The nature of the opaque cylinder is difficult to ascertain using optical microscopy. This is the subject of the present note. To study the inside of the opaque cylinder we use several experimental methods based on imaging the failed region: optical microscopy, laser Raman spectroscopy and scanning electron microscopy. Mechanical models, including FEM analysis and analytic equations based on the shear-lag approach, are used to discuss the experimental work. The nature and growth mechanism of the opaque cylinder are of importance in defining the parameters and/or contributions that appear in both the force balance and the energy balance schemes.

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HUSEBY, MORTEN, and JOHN GRUE. "An experimental investigation of higher-harmonic wave forces on a vertical cylinder." Journal of Fluid Mechanics 414 (July 10, 2000): 75–103. http://dx.doi.org/10.1017/s0022112000008533.

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First- and higher-harmonic wave loads on a vertical circular cylinder are investigated experimentally in a wave tank of small scale. The incoming waves are (periodic) Stokes waves with wave slope up to 0.24. A large set of waves which are long compared to the cylinder radius is calibrated. The first seven harmonic components of the measured horizontal force on the cylinder are analysed. The higher-harmonic forces are significantly smaller than the first-harmonic force for all wave parameters. The measurements are continued until the wave amplitude is comparable to the cylinder radius, where the second-, third- and fourth-harmonic forces become of comparable size. Comparison with existing perturbation and fully nonlinear models shows, with a few exceptions, an overall good agreement for small and moderate wave amplitude. A fully nonlinear model agrees with the experiments even up to the seventh-harmonic force for part of the amplitude range. For the large amplitudes the models mostly give conservative predictions. It is important that the distance from the wave maker to the cylinder is large in order to avoid parasitic effects in the incoming wave field. The limited width of the wave tank is not important to the results except when close to resonance.

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Journal articles on the topic 'In-cylinder models'

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