In this study, two dimensional unsteady flows of cylinder and cylinder with additional fairing close to a free surface were numerically investigated. The governing momentum equations were solved by using the Semi Implicit Method for Pressure Linked Equations(SIMPLE). The Volume of Fluid(VOF) method applied to simulate a free surface. Non- uniform grid structures were used in the simulation with denser grids near the cylinder. Under the conditions of Reynolds number 150624, 271123, 210874 and 331373, the cylinders were simulated with different depths of invasion. It was shown that the flow characteristics were influenced by submergence depth and Reynolds numbers. When the cylinder close to the free surface, the drag coefficient, lift coefficient and Strouhal numbers will increase due to the effect of free liquid surface on vortex shedding. With additional fairing, can effectively reduce the influence of the free surface on the drag coefficient. Fairing will reduce lift coefficient at high Reynolds numbers, but increase lift coefficient when Reynolds numbers are small. Fairing can effectively reduce Strouhal numbers, thus can well suppress the vortex induced vibration

This work aims to analyze the thermal deformation of a thermal shield laminated material under a uniform or one-sided heating of up to 600°C/min. The material is made of a fiberglass composite polymer material based on phenol-phormaldehyde matrix. This work describes the method used to study the kinetics of thermal deformation of the composite material at different heating rates and a high-temperature of gas flow (2500°C). The state of the stressed-deformed samples made of a reinforced plastic is computed and used to measure the expanded temperature of the materials under one-sided heating. It is shown that under both force and thermal loading, the linear dependence of the coefficient of thermal deformation Т on temperature, stresses in the sample developed to prevent the bending of free samples. For a bent sample, there is no stress gradient ( = 0) under increased heating rate of the loaded samples, leading to an increase in the stress gradient values. The data are compared with dilatometry results obtained at a uniform temperature field and heating rates of 20 to 1100°C. Key words:  Thermal shield, spacecraft, re-entry, composite material, high temperature, fiberglass, dilatometer.

In any application of wall-bounded or shear fluid flows, near-wall boundary layer and shear layer are the places of struggle between viscous and inertial forces.After development and spread of using wall functions for modeling near-wall region of boundary layer in wall-bounded turbulent flows, the importance of accurate prediction and modeling of different layers of boundary layer, particularly the so-called logarithmic layer becomes more crucial in aerodynamics.Due to the intrinsic characteristics of flow structure in log-layer and wide-spread applications of wake flows, the presence of these characteristics in wake flows rather than wall-bounded flows opens a new window to the researchers to investigate the possibility of using log-law within wake regions, particularly on wake centerline for modeling purposes.On the applications of wake modeling and studying, we can point out to wing and blade trailing edge design, exhaust flow of pipes and ducts (e.g.nozzle exhaust or internal flow of polymers in dimpled pipes), and vortex generator design which are just a few examples of the areas with great interest in both fundamental scientific research, that is, developing optimum and accurate Computational Fluid Dynamics (CFD) tools and their industrial applications.In this article, a brief description about different approaches, previous efforts and case studies, and similar analogous problems is presented to give a better perception to the future researchers.

Rice is one of the most important cereal crop in the world. This paper present the design and performance evaluation of a rice hulling machine fabricated for removing chaffs from paddy rice as the consumer’s demand for rice requires the most hygienic, easy and less time consuming process. The design was segmented into the hopper and housing (processing) unit, the frame support and the power transmission unit. The housing unit consists of the upper and lower body where the sieve, hulling blade and cylinder is enclosed. The machine is powered by a 3.0 H.P. 950 rpm electric motor via a V-belt mechanism which deliverers the power requirement to the shaft on which the hulling cylinder is mounted. The hulling cylinder presses the paddy rice against the hulling blade to remove the chaff. The paddy rice is fed into the housing unit for processing through the machine hopper. The probability failure of the machine during loading has been minimized by proper material selection and using a factor of safety of 4 in the design process. The machine was designed to process about 8 kg of rice for small scale production. Performance evaluation of the machine shows that its efficiency is within the range of 83 to 88%, the hulling capacity is within the range of 22 to 25 kg/h and the maximum efficiency is at 5 kg paddy rice hopper loading which is about 60% of the hoppers’ volume. Key words: Rice, hulling, dehusking machine, paddy, fabrication. &nbsp

Fused deposition modeling (FDM) is one of the most adaptable additive manufacturing method owing to the cost-effectiveness and environment-friendly nature. However, FDM technique still possesses major difficulties in terms of poor surface quality because of adding layer by layer manufacturing process for the prototypes. It is desirable to explore an efficient technique for FDM parts to enhance the poor surface quality and dimensions precision. In the present paper, an effort has been made to enhance the surface quality and optimize the critical processing parameter of FDM based benchmark using vapor smoothing process (VSP). A comparative experimental study has been performed by design of experiments (DOE), Taguchi technique to find the influence of input design parameters on the surface finish of benchmark FDM parts. The results of the present investigation show that VSP treatment improves the surface quality of FDM parts to micro level with negligible dimensional variation. It is observed that improved surface quality is found in the 1,2, -Dichloroethane chemical at 90° part build orientation, 0.25 mm layer thickness, 10% fill density and 90 second exposure times.

The rapid development of China's automobile industry has brought ever-increasing impact on resources, energy and environment, the energy-saving and new energy vehicles come into being accordingly. This article firstly systematically introduces the technical route of energy-saving and new energy vehicles of China, focusing on the key bottleneck problems arising from the construction process of current assessment system of the technical route for energy-saving and new energy vehicles, establishes the energy-saving and new energy vehicle business model assessment index system afterward based on the comparative analysis on energy-saving and new energy vehicle business assessment model and the full life cycle theory, and finally makes prospects and forecasts on vital problems of system boundary, dynamic optimization, simulation system of full life cycle assessment of energy-saving and new energy vehicle.

The thermal balance state of high-speed and heavy-load gear transmission system has an important influence on the performance and failure of gear transmission and the design of gear lubrication system. Excessive surface temperature of gear teeth is the main cause of gluing failure of gear contact surface. To investigate the gear heat distribution in meshing process and discuss the effect of thermal conduction on heat distribution,a finite element model of spur gear is presented in the paper which can represent general involute spur gears. And a simulation approach is use to calculate gear heat distribution in meshing process. By comparing with theoretical calculation, the correctness of the simulation method is verified, and the heat distribution of spur gear under the condition of heat conduction is further analyzed. The difference between the calculation results with heat conduction and without heat conduction is compared. The research has certain reference significance for dry gear hobbing and the same type of thermal-structural coupling analysis.

To overcome the weakness of conventional models in describing compressing flow especially in start and end stages the shear rate derivative was added to the right side of PTT constitutive equation. The ability of describing the well-known ‘shear shinning’ and ‘stretch harden’ phenomena was first illustrated by theoretical analysis. Then the governing equations for compressing flow were established in terms of incompressible and isothermal fluid, and the numerical method was constructed to discretize the equations and get the compressing flow solutions. The experiments with four melt temperatures were conducted and the corresponding simulations were performed. The better agreements with experimental data indicates the modified PPT model is superior to the original PTT model in prediction of compressing flow. In addition, the proposed model is also validated with low and high compressing speed experiments.

With the continuous development of urban construction projects in HebeiProvince, the rise and development of high-rise buildings and undergroundengineering, the design and research of foundation pit support structure has become more and more important. The design of the foundation pit support structure directly affects the settlement and position changes of the building itself and the surrounding stratum. In this paper, the characteristics of foundation pit support are analyzed, and the related theories of finite element analysis method are introduced. Combined with the actual situation of Hebei Province, the finite element analysis method is used to simulate the construction method of foundation pile anchor support structure system. The design was analyzed and studied.

The unhealthy and destructive motion exhibited in moving, operating or rotating machinery is called vibration. It is also observed as any oscillatory motion of a mechanical system about its equilibrium point. Clearly, vibration can thus be unhealthy and destructive which is the reason for its undesirability. However, it can also be good and useful as observed in some mechanical and construction equipment. Vibration can be observed in pendulum set in motion, a plucked guitar string, vehicles driven on rough terrain and geological activities like earthquakes. It is also observed in vibratory conveyors, washing machines, electric massaging units, compactors, hoppers and the like. Thus the focus of vibration study is to reduce vibration through proper design of machines and their mountings. In this connection, the mechanical engineer tries to design the engine or machine to minimize imbalance, while the structural engineer tries to design the supporting structure to ensure that the effect of the imbalance is harmless. In spite of its detrimental effects, vibration can be utilized profitably in several consumer and industrial applications. The efficiency of certain machining, casting, forging, and welding processes has been found to be improved by vibration. It is also employed to simulate earthquakes for geological research and to conduct studies in the design of nuclear reactors. Clearly, vibration studies concentrated on the undesirability of vibration and how to reduce its effect. The studies also stressed the need to improve the efficiency of applications where vibration is desirable. The aforementioned studies notwithstanding and going by the recent earthquake in Mexico as well as the flooding and storm in various parts of the world, the last is yet to be heard about the devastating effect of vibration. This work presents the various vibration types through worked examples. It may open a floodgate of new investigations into the effect of the various vibration types which may in turn lead to new designs and fabrication of appropriate engineering devices to control and reduce to the barest minimum the harmful effect of the various vibration types. Key words: Vibration, mechanical device, engineering systems.