Jin Pang^1,*, Di Luo², Haohong Gao³, Jie Liang⁴, Yuanyuan Huang¹, Qi Liu³

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.1, pp. 39-51, 2019, DOI:10.32604/fdmp.2019.06136

Abstract High-pressure deep shale gas reservoirs are usually highly stress-sensitive. When the reasonable production mode of shale gas well is built, the impact of strong stress sensitivity should be fully considered. First, this study calculated the relationship between permeability and formation pressure under different elastic modulus based on the shale lithology of Long Ma Xi formation in Sichuan Basin by testing and analysing the mechanical parameters of the rock. According to numerical simulation result, when the elastic modulus exceeds 14.0 GPa, the stress sensitivity of the matrix will slight affect the cumulative gas production of shale gas. Second, the changing relation… More >

Xuebo Zhang^{1, 2, 3}, Zhiwei Jia^{1, 2, 3, *}

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.1, pp. 53-61, 2019, DOI:10.32604/fdmp.2019.04779

Abstract The influence of ground stress was quantitatively analyzed on coal seam gas pressure and gas content in this paper. Mining activities in coal mine can result in stress concentration in the coal (rock) body around the mining space, but porosity of the coal seam would not change too much. Therefore, gas pressure and gas content in the coal seam are slightly affected. Studies showed that the free gas was gradually transformed into adsorbed gas, and the gas adsorption volume was small, and then gas pressure increases roughly linearly when the porosity decreased because of stress influence. Additionaly, when porosity of… More >

A. Khechiba¹, Y. Benakcha¹, A. Ghezal¹, P. Spetiri²

FDMP-Fluid Dynamics & Materials Processing, Vol.14, No.2, pp. 137-154, 2018, DOI: 10.3970/fdmp.2018.04054

Abstract This work investigates the dynamic behavior of a pulsatile flow electrically conducting through porous medium in a cylindrical conduit under the influence of a magnetic field. The imposed magnetic field is assumed to be uniform and constant. An exact solution of the equations governing magneto hydro-dynamics (MHD) flow in a conduit has been obtained in the form of Bessel functions. The analytical study has been used to establish an expression between the Hartmann number, Darcy number and the stress coefficient. The numerical method is based on an implicit finite difference time marching scheme using the Thomas algorithm and Gauss Seidel… More >

Anupam Bh,ari¹, Vipin Kumar²

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.3, pp. 359-375, 2014, DOI:10.3970/fdmp.2014.010.359

Abstract The purpose of this paper is to study the flow characteristics of a ferrofluid revolving through a porous medium with a magnetic-field-dependent viscosity in the presence of a stationary disk. A Finite Difference Method is employed to discretize the set of nonlinear coupled differential equations involved in the problem. The discretized nonlinear equations, in turn, are solved by a Newton method (using MATLAB) taking the initial guess with the help of a PDE Solver. Results displayed in graphical form are used to assess the effect of the variable viscosity and porosity parameters on the velocity components. The displacement thickness of… More >

Yu. Gaponenko¹, I. Ryzhkov², V. Shevtsova³

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.1, pp. 75-98, 2010, DOI:10.3970/fdmp.2010.006.075

Abstract Gas-liquid flows in annulus are analyzed for fluids in large range of viscosity ratios. The geometry corresponds to a liquid bridge co-axially placed into an outer cylinder with solid walls. The internal core consists of solid rods at the bottom and top, while the central part is a relatively short liquid zone filled with viscous liquid and kept in its position by surface tension. The gas enters into the annular duct and entrains initially quiescent liquid. The flow structures in the liquid and gas are obtained numerically for different shapes of solid rods. Solution for fully developed flow in annulus… More >

J.R. Lin¹, P.J. Li², T.C. Hung³

FDMP-Fluid Dynamics & Materials Processing, Vol.9, No.4, pp. 419-434, 2013, DOI:10.3970/fdmp.2013.009.419

Abstract On the basis of the Shliomis ferrofluid model (1972) together with the micro-continuum theory of Stokes (1966), the influences of non-Newtonian ferrofluids on the steady-state performance of long journal bearings have been investigated in the present paper. Analytical solutions for bearing performances are obtained from the non-Newtonian ferrofluid Reynolds-type equation. Comparing with the Newtonian non-ferrofluid case, the effects of non-Newtonian ferrofluids with applied magnetic fields provide an increase in the zero pressure-gradient angle and the load capacity, and a decrease in the friction parameter, especially for a larger non-Newtonian couple stress parameter and magnetic Langevin’s parameter. For the long journal… More >

P. Yu¹, T. S. Lee¹, Y. Zeng¹, H. T. Low²

FDMP-Fluid Dynamics & Materials Processing, Vol.1, No.3, pp. 235-246, 2005, DOI:10.3970/fdmp.2005.001.235

Abstract A numerical model is developed for the investigation of flow field and mass transport in a micro-bioreactor, of working volume below 5 ml, in which medium mixing is generated by a magnetic stirrer-rod rotating on the bottom. The flow-field results show that a recirculation region exists above the stirrer rod and rotates with it; the related fluid mixing is characterized by a circulation coefficient of up to 0.2 which is about five times smaller than that of a one-litre stirred-tank bioreactor. The oxygen transfer coefficient is less than 5 h^-1 which is two orders smaller than that of a 10-litre… More >

K. S. Alan¹

CMC-Computers, Materials & Continua, Vol.44, No.1, pp. 1-21, 2014, DOI:10.3970/cmc.2014.044.001

Abstract In the framework of the piecewise homogeneous body model with the use of the three-dimensional geometrically nonlinear exact equations of the theory of elasticity, the method developed for the determination of the stress distribution in the nanocomposites with unidirectional locally curved and hollow nanofibers is used to investigate the normal stresses acting along the nanofibers. Furthermore, it is assumed that the body is loaded at infinity by uniformly distributed normal forces which act along the nanofibers and the crosssection of the nanofibers and normal to its axial line, is a circle of constant radius along the entire nanofiber length. For… More >

Ping’en Li^1,2, Xianyue Su^1,3

CMC-Computers, Materials & Continua, Vol.8, No.3, pp. 173-194, 2008, DOI:10.3970/cmc.2008.008.173

Abstract Applying the Stroh theory and based on the works of Hwu and Ting (1989), the complex function solution of stress and displacement fields around an open borehole in intrinsic anisotropic formation under horizontal terrestrial stress field is obtained. For cross-dipole flexural wave propagation along borehole axis, using the perturbation method, the acoustoelastic equation describing the relation between the alteration in phase velocity and terrestrial stress as well as formation intrinsic anisotropy is derived. At last, the numerical examples are provided for both the cases of fast and slow formation where the symmetry axis of a transversely isotropic (TI) formation makes… More >

Yan Zhang¹, Shengping Shen¹

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 17-22, 2008, DOI:10.3970/cmc.2008.008.017

Abstract In this paper, an existed model for adsorption-induced surface stress is modified with physical clarity, based on the equilibrium of force. In the proposed multiscale model, a four-atom system is used, instead of the existed three-atom system which did not consider the force equilibrium. By analyzing the force state of an atom, the thickness of the first layer atoms can be determined. Thus, the proposed model does not need to determine the layer-thickness by experiments or artificially. The results obtained from the proposed model agree very well with the experimental data. This paper is helpful to investigate the atomistic theory… More >