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Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectivesPoiseuille flow widely exists in the industry, but the stability and reliability of the moving particle semi-implicit (MPS) method in the simulation of wall shear flow such as Poiseuille flow need to be verified. MethodsThe meshless solver MLParticle-SJTU, which was developed independently based on the MPS method, is used to simulate Poiseuille flow in 2D pipes under different Reynolds numbers by establishing the inflow boundary and no-slip wall boundary, and the fluid is an incompressible Newtonian fluid. The numerical simulation results and theoretical results are then compared to verify the accuracy of the former. ResultsThe results show that the velocity profile of Poiseuille flow is parabolic when the flow is fully developed, and the error of the numerical simulation results is within 5% compared with the theoretical results under different Reynolds numbers. ConclusionThis study shows that the MPS method is effective and reliable for simulating 2D Poiseuille flow under the boundary conditions proposed in this paper.

Low-speed flow experiments in which ultra-fine copper tubes are used to simulate micro-fractures in carbonate strata are conducted to analyze the variations of gas flow state in fractures of different fracture heights, determine flow state transition limit and transition interval, and establish the calculation method of flow state transition limit. The results show that the ideal Hagen-Poiseuille flow is the main form of gas flow in large fractures. Due to the decrease of fracture height, the gas flow in the fracture changes from Hagen-Poiseuille flow with ideal smooth seam surface to non-Hagen-Poiseuille flow, and the critical point of the transition is the boundary of flow state transition. After the fracture height continues to decrease to a certain extent below the boundary of the flow state transition fracture height, the form of gas flow gradually changes to the ideal Darcy flow, thus the transition interval of the gas flow state in the closing process of fracture can be determined. Based on the three-dimensional microconvex body scanning of the fracture surface, the material properties of fracture and properties of fluid in the fracture, a method for calculating the boundary of flow state transition is established. The experimental test and theoretical calculation show that the limit of the fracture height for the transition from pipe flow to Darcy flow is about twice the sum of the maximum height of the microconvex bodies on the upper and lower sides of the fracture.

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at enriching teaching contents and experimental teaching methods of fluid dynamics course, several classical problems in fluid mechanics have been simulated using LBM (Lattice Boltzmann method). An integrated virtual simulation experiment platform encapsulated by Matlab GUI (Graphic User Interface) is developed to improve traditional teaching mode and teaching efficiency. Three modules, lid-driven flow module, Poiseuille flow module and Karman vortex street module, are included in this platform. The simulation results can be displayed directly by inputting operating parameters on the user interface of the platform. Compared with the traditional teaching mode and experiment, this integrated virtual simulation experiment platform has the advantages of good visualization, fast calculation speed, clear user interface, simple operation, low teaching cost and easy communication, which is beneficial to the understanding of the students on the abstract concepts and complex flow patterns in fluid dynamics course. Owing to the increase in the interest of the students and the efficiency of classroom teaching, this platform deserves to be popularized in the teaching of fluid mechanics. [ABSTRACT FROM AUTHOR]

Simulation of the non-Newtonian fluid flow is an interesting problem for engineers. As a relatively new particle-based method, the material point method (MPM), combining the advantages of both the Lagrangian algorithm and the Eulerian algorithm, has been widely and effectively used to solve complex engineering problems. The plane Poiseuille flow and Couette flow of the shear thickening and shear thinning cross fluid and power-law fluid were studied with the artificial state equations for the MPM. The results show that, the simulation with the MPM for the Newtonian fluid is in good agreement with the theoretical solution and the MPM simulates the shear thinning and shearing thickening of the non-Newtonian fluid exactly. The results confirm the applicability of the MPM for simulation of the non-Newtonian fluid flow and expand the application field of the MPM. [ABSTRACT FROM AUTHOR]

Applying the optimal homotopy asymptotic method (OHAM) to study three nonlinear problems, plane Couette flow, plane Poiseuille flow and plane Couette-Poiseuille flow, of the Oldroyd 6-constant fluid. Firstly, the governing equation and boundary condition of plane Couette flow, plane Poiseuille flow and plane Couette-Poiseuille flow in the Oldroyd 6-constant fluid were introduced respectively. Then applying the optimal homotopy asymptotic method was used to solve the problem, and carrying out some simulations. Finally, the effect of the slip parameter on the velocity profile was discussed based on the simulations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In a liquid-solid two-phase flow, small and low volume concentration of the solid particles make the uncontrollable movement in liquid phase flow field under the gravity, the Stokes drag force, the Saffman force, the pressure gradient force, the virtual mass force and so on. In order to control the law of the particle's motion, it is necessary to add the external controllable force to the liquid-solid two-phase flow field. Therefore, the particle's motion is changed by changing the value of the external force. In the vertical direction of the two-dimension Poiseuille flow field, a high-voltage electrostatic field was designed. That is to say, the controllable electrostatic field force was applied to the charged solid particles. In addition, the charged particle's kinematics model was established under the two-dimension Poiseuille flow and the high-voltage electrostatic field in the bounded viscous fluid field, then the movement law and the main conditions effecting the movement of the charged solid particle were analyzed. According to the charged particle's kinematics model in the multi-physics field coupling conditions, solid and liquid two-phase separators were designed in this paper. The folding-shaped dust collection media was installed on the separator at the direction of liquid phase flow, and 15 kV electrostatic was added to the positive and negative electrode of the separator. A particle separation experiment was conducted using this separator on L-HM32# used antiwear hydraulic oil provided by the Shandong Hengye Electromechanical Technology Company, and the used oil cleanliness level was NAS12. In the case of maintaining a constant liquid velocity, the hydraulic oil sample was taken once from the oil storage tank of the solid-liquid separator every three hours, and then the number of particles in the oil sample was measured respectively for the 2-5, 5-15, 15-25, 25-50, 50-100 μm diameter particles using the AMF particle counter designed by the Markus Klotz Gmbh company. After working 12 hours, the number of 2-100 μm particles were significantly reduced, the various size particles separation efficiency was about 95%, and the hydraulic oil cleanliness level reached NAS4. After working 24 hours, the number of 2-5 and 5-15 μm particles in the oil were continuously reduced, but the purification effect was not obvious. On the contrary, the number of 15-100 μm particles in the oil were increased slightly. Moreover, the largest increase in the number was the 50-100 μm big particles. That is to say, the solid-liquid separation efficiency will decrease when the separator works more than 12 hours. The experiment illustrated that the movement law of the charged particles in two-dimensional Poiseuille flow field was effectively controlled. At the same time, the experiment achieved a highly efficient solid-liquid separation and sorting of solid particles, which improved the purification rate and recycling utilization rate of waste oil. By studying the kinetics law of the particles in the two-phase flow of the two-dimensional Poiseuille under the external force, a valuable reference is provided to recycling and reuse of the waste industrial oil, purification of the pollution water, and energy conservation. [ABSTRACT FROM AUTHOR]