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Aiming at the problems of easy spalling and roof fall in the soft coal seam under the influence of strong deep mining, the 31020 working face of Pingdingshan No.12 coal mine is used as the engineering background, combined with nuclear magnetic resonance, etc. Various technical methods have carried out research on the water absorption characteristics, composition, micro-structure, and fracture morphology of coal at different immersion time. The experimental results show that the coal sample in this mining area belongs to coking coal under the bituminous coal category. The main inorganic substances are kaolinite and calcite.

Ethylene plays important roles in plant growth and development, but the regulation of ethylene signaling is largely unclear, especially in crops such as rice (Oryza sativa). Here, by analysis of the ethylene-insensitive mutant mao huzi 11 (mhz11), we identified the GDSL lipase MHZ11, which modulates ethylene signaling in rice roots. MHZ11 localized to the endoplasmic reticulum membrane and has acyl-hydrolyzing activity. This activity affects the homeostasis of sterols in rice roots and is required for root ethylene response. MHZ11 overexpression caused constitutive ethylene response in roots. Genetically, MHZ11 acts with the ethylene receptor ETHYLENE RESPONSE SENSOR2 (OsERS2) upstream of CONSTITUTIVE TRIPLE RESPONSE2 (OsCTR2) and ETHYLENE INSENSITIVE2 (OsEIN2). The mhz11 mutant maintains more OsCTR2 in the phosphorylated form whereas MHZ11 overexpression promotes ethylene-mediated inhibition of OsCTR2 phosphorylation. MHZ11 colocalized with the ethylene receptor OsERS2, and its effect on OsCTR2 phosphorylation requires ethylene perception and initiation of ethylene signaling. The mhz11 mutant overaccumulated sterols and blocking sterol biosynthesis partially rescued the mhz11 ethylene response, likely by reducing receptor-OsCTR2 interaction and OsCTR2 phosphorylation. We propose that MHZ11 reduces sterol levels to impair receptor-OsCTR2 interactions and OsCTR2 phosphorylation for triggering ethylene signaling. Our study reveals a mechanism by which MHZ11 participates in ethylene signaling for regulation of root growth in rice.

The angle-sensitive photonic bandgap (PBG) is one of the typical features of one-dimensional photonic crystals. Based on the phase-variation compensation effect between the dielectric and hyperbolic metamaterials (HMMs), angle-insensitive PBGs can be realized in photonic hypercrystals. However, since hypercrystals are usually constructed using metal components, these angle-insensitive PBGs are mostly limited to narrow bandwidths in visible range. Here, we replace metal with indium tin oxide (ITO) to construct HMMs in the near-infrared range. In these ITO-based HMMs, we experimentally demonstrate the negative refraction of light in transverse magnetic polarization. With this HMM component, we realize a photonic hypercrystal with an angle-insensitive PBG in the wavelength range of 1.15–2.02 µm. These ITO-based hypercrystals with large angle-insensitive PBGs can find applications in near-infrared reflectors or filters.

In order to tackle the problem of the high failure rate of blades of large wind turbine units due to lightning damage, a new lightning protection system (NLPS) for wind turbine blades is proposed based on the lightning damage mechanism of blades. Firstly, 10 high-voltage discharge tests are performed for blades with and without the NLPS to study the effect of lightning protection. The results show that when the surface of the blade without the NLPS is struck by lightning 10 times, the damage rate of the blade is 100%, for the blade with the NLPS and the lightning attachment position is always on the NLPS in 10 discharge tests, the damage rate of blades is 0% and the lightning protection rate of blades is 100%, indicating that the lightning protection effect for blades with the NLPS is greatly improved. Moreover, the static electric fields of the blades with and without the NLPS are calculated. The results show that the NLPS can shield the electric field around the lower lead wire of the blade, thus effectively reducing the electric field intensity. The NLPS initiates the upward leader more easily than the lower lead wire, therefore, the lightning attachment point is located on the NLPS, thus protecting the blade. Secondly, the aerodynamic and aero-noise characteristics of the blade with and without the NLPS are calculated. The results indicate that the NLPS has little influence on the aerodynamic performance of the blade but has some influence on the aero-noise of the blade. The aero-noise of the airfoil can be reduced at angles of attack of 4&deg, 8&deg, 11&deg, and 15&deg, but the influence of different phase angles of the airfoil on the amplitude of the sound pressure level (SPL) varies. The aero-noise of the airfoil with the NLPS decreases by 16% and 8% at angles of attack of 4&deg, and 8&deg, respectively. In general, the design of the NLPS reaches the desired requirements, but it still needs to be further optimized in combination with the blade manufacturing process.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Numerical simulation technique of two-dimensional variable-order time fractional advection-diffusion equation is developed in this paper using radial basis function-based differential quadrature method (RBF-DQ). To the best of the authors’ knowledge, this is the first application of this method to variable-order time fractional advection-diffusion equations. For the general case of irregular geometries, the meshless local form of RBF-DQ is used and the multiquadric type of radial basis functions is selected for the computations. This approach allows one to define a reconstruction of the local radial basis functions to treat accurately both the Dirichlet and Neumann boundary conditions on the irregular boundaries. The method is validated by the well documented test examples involving variable-order fractional modelling of air pollution. The numerical results demonstrate that the proposed method provides accurate solutions fortwo-dimensional variable-order time fractional advection-diffusion equations.

Biological soil crusts (biocrusts) are widely distributed in arid and semiarid ecosystems and provide critical ecological functions. Understanding how biocrusts change across broad regional scales allows us to manage them more effectively under changing climates and land-use pressures. Based on field surveys, we used boosted regression trees and correlation analysis to examine the changes in cover, distribution and developmental characteristics of biocrust mosses and cyanobacteria, and environmental factors at 40 sites in the Mu Us Sandland in northwestern China. We found that higher elevation sites (~1342 m) were the most suitable for biocrust distribution, and preferred sites were characterized by greater vegetation cover (>43%), values of the aridity index (>0.34), slope (>6.6°), soil pH (>8.85) and soil organic carbon (>0.50%). Increasing levels of disturbance (>1.15 kg dung ha−1) suppressed biocrusts. Moss crust development (e.g., biomass, thickness, bulk density) was significantly positively related to vegetation cover, aridity index, and soil organic carbon, and moss crusts tended to prefer shady shrub communities at low elevations. Shady and steep (5 – 15°) slopes and higher soil nutrient contents were positively correlated with cyanobacteria development. Reduced rainfall and increasing disturbance intensity would reduce the distribution and development of biocrusts. Our study provides a basis for informed decision making about how to manage moss and cyanobacterial crusts in the Mu Us Sandland as the region becomes hotter and drier.

During the operation of wind turbines, flow separation appears at the blade roots, which reduces the aerodynamic efficiency of the wind turbine. In order to effectively apply vortex generators (VGs) to blade flow control, the effect of the VG spacing (&lambda, ) on flow control is studied via numerical calculations and wind tunnel experiments. First, the large eddy simulation (LES) method was used to calculate the flow separation in the boundary layer of a flat plate under an adverse pressure gradient. The large-scale coherent structure of the boundary layer separation and its evolution process in the turbulent flow field were analyzed, and the effect of different VG spacings on suppressing the boundary layer separation were compared based on the distance between vortex cores, the fluid kinetic energy in the boundary layer, and the pressure loss coefficient. Then, the DU93-W-210 airfoil was taken as the research object, and wind tunnel experiments were performed to study the effect of the VG spacing on the lift&ndash, drag characteristics of the airfoil. It was found that when the VG spacing was &lambda, /H = 5 (H represents the VG&rsquo, s height), the distance between vortex cores and the vortex core radius were approximately equal, which was more beneficial for flow control. The fluid kinetic energy in the boundary layer was basically inversely proportional to the VG spacing. However, if the spacing was too small, the vortex was further away from the wall, which was not conducive to flow control. The wind tunnel experimental results demonstrated that the stall angle-of-attack (AoA) of the airfoil with the VGs increased by 10&deg, compared to that of the airfoil without VGs. When the VG spacing was &lambda, /H = 5, the maximum lift coefficient of the airfoil with VGs increased by 48.77% compared to that of the airfoil without VGs, the drag coefficient decreased by 83.28%, and the lift-to-drag ratio increased by 821.86%.

In order to explore the effect of the installation angle of vortex generator (VG) on boundary-layer flow control, the vortex characteristics of plate VG and their effect on the aerodynamic characteristics of an airfoil was studied numerically and using wind tunnel experiments. The effects of five VG installation angles (&beta, ) of 10&deg, 15&deg, 20&deg, 25&deg, and 30&deg, on the characteristics of vortices were studied. The results show that the strength of vortices on the leeward side of VG increases with an increased installation angle until, eventually, the vortex core breaks down. During the downstream development of the VG leading-edge separation vortices, these vortices deviate in the radial direction. The larger the installation angle, the larger this deviation distance in the radial direction becomes. The effects of installation angle on the aerodynamic performance of airfoils were studied in a wind tunnel using the same five VG installation angles. The results show that VG can delay flow separation on the airfoil suction surface, thereby increasing lift and reducing drag. The stall angle of the airfoil with VG was increased by 10&deg, When the installation angle of the VG was 20&deg, the maximum lift coefficient of airfoil increased by 48.77%. For an airfoil angle of attack (AoA) of 18&deg, the drag of the airfoil decreased by 88%, and the lift-drag ratio increased by 1146.04%. Considering the best overall distribution of lift-drag ratio, the positive effect of the VG was found to be when &beta, = 20&deg, and the worst VG effectiveness was observed at &beta, = 30&deg

Large-scale organized motions (commonly referred to coherent structures) and flow topology of a transitional separated-reattached flow have been visualised and investigated using flow visualisation techniques. Two geometrical shapes including two-dimensional flat plate with rectangular leading edge and three-dimensional square cylinder are chosen to shed a light on the flow topology and present coherent structures of the flow over these shapes. For both geometries and in the early stage of the transition, two-dimensional Kelvin-Helmholtz rolls are formed downstream of the leading edge. They are observed to be twisting around the square cylinder while they stay flat in the case of the two-dimensional flat plate. For both geometrical shapes, the two-dimensional Kelvin-Helmholtz rolls move downstream of the leading edge and they are subjected to distortion to form three-dimensional hairpin structures. The flow topology in the flat plate is different from that in the square cylinder. For the flat plate, there is a merging process by a pairing of the Kelvin-Helmholtz rolls to form a large structure that breaks down directly into many hairpin structures. For the squire cylinder case, the Kelvin-Helmholtz roll evolves topologically to form a hairpin structure. In the squire cylinder case, the reattachment length is much shorter and a forming of the three-dimensional structures is closer to the leading edge than that in the flat plate case.

To explore the effect of the height of vortex generators (VGs) on the control effect of boundary-layer flow, the vortex characteristics of a plate and the aerodynamic characteristics of an airfoil for VGs were studied by both wind tunnel experiments and numerical methods. Firstly, the ratio of VG height (H) to boundary layer thickness (δ) was studied on a flat plate boundary layer; the values of H are 0.1δ, 0.2δ, 0.5δ, 1.0δ, 1.5δ, and 2.0δ. Results show that the concentrated vortex intensity and VG height present a logarithmic relationship, and vortex intensity is proportional to the average kinetic energy of the fluid in the height range of the VG. Secondly, the effects of height on the aerodynamic performance of airfoils were studied in a wind tunnel using three VGs with H = 0.66δ, 1.0δ, and 1.33δ. The stall angle of the airfoil with and without VGs is 18° and 8°, respectively, so the VGs increase the stall angle by 10°. The maximum lift coefficient of the airfoil with VGs increases by 48.7% compared with the airfoil without VGs, and the drag coefficient of the airfoil with VGs is 84.9% lower than that of the airfoil without VGs at an angle of attack of 18°. The maximum lift–drag ratio of the airfoil with VGs is lower than that of the airfoil without VGs, so the VGs do not affect the maximum lift–drag ratio of the airfoil. However, a VG does increase the angle of attack of the best lift–drag ratio.

Vortex generators (VGs) are an effective way to control flow separation in wind turbine. To understand the mechanism of VGs controlling flow separation, the flow field around airfoil Du97W300 with VGs was simulated and analyzed with CFD tools, and this numerical method is validated through the comparison between the numerical results and the experimental results. Furthermore, the flow fields around airfoil equipped with four different types of VGs are calculated and analyzed. The results show that the helical vortex induced by counter-rotating VGs develop approximately along streamwise direction; these types of VGs can cause a delay in stall and enhance the maximum airfoil lift coefficient. However the helical induced vortex actuated by the co-rotating VGs develop nearly along vortex generator direction and cannot cause a delay in stall effectively. In the counter-rotating VGs, the Q integration (the character parameter of induced vortex) of rectangular is twice of the triangle, and the Q integration of the forward triangle is almost equal to the backward triangle VGs.

We readdress a classical and practical problem as to whether viscoelasticity can have a measurable and beneficial effect on lubrication performance in thin film flows. In this paper, the viscoelasticity of the fluid is described by general Maxwell–Oldroyd type models. More specifically, it is modeled by the Phan-Thien–Tanner constitutive equations. A perturbation analysis for all the primary variables is carried out with the Deborah number as the perturbation parameter. The sequence of governing equations that results from the perturbation procedure is solved analytically up to first order in the Deborah number. Despite the inherent limitations of the perturbation method, the approach presented here demonstrates a reasonable way to determine the viscoelastic effects on lubrication performance in thin film flows. Numerical solutions indicate that there is a significant enhancement of the viscoelastic pressure when the minimum film thickness is sufficiently small. This mechanism suggests that viscoelasticity does indeed enhance the lubricant pressure field and produce a beneficial effect on lubrication performance, which is consistent with experimental observations.

There is no temperature stress and temperature curling according to the present cement concrete pavement design, when the temperature gradient of cement concrete pavement in service is zero, and it does not consider the effect of Built-in curling caused in early-age setting process of cement concrete to cement concrete pavement in service. In fact, there is Built-in curling in cement concrete slab when it is after the completion of the cement concrete slab is poured, and the curling is mainly upward. It is in the setting process, when cement concrete is on the final set, the cement concrete is at the critical moment when is just able to bear load, and it exists temperature gradient but no strain in the pavement slab, the temperature gradient is known as "Built-in construction temperature gradient" in AASHTO2002 design guidance, and it is the important part of the Built-in curling. In this paper, cement concrete beam specimens were poured in outdoor and temperature sensor and strain sensor were buried in the cement concrete specimens to detect early-age internal temperature field and strain field, and then the study of Built-in curling and Built-in construction temperature gradient were carried out.

A new Chebyshev spectral element method has been developed in this paper, in which exact quadratures are used to overcome a shortfall of the Gauss-Chebyshev quadrature in variational spectral element projections. The method is validated with the Stokes and the Cauchy-Riemann problems. It is shown that an enhancement of the approximation convergence rate is attained, and numerical accuracy is much better than that from the Gauss-Lobatto-Legendre spectral element method. The paper addressed and assessed some of the issues concerning the numerical accuracy on the Chebyshev spectral element method.A new Chebyshev spectral element method is developed by using exact quadratures in computing spectral elements.The method is validated with the Stokes and the Cauchy-Riemann problems.Numerical results show that an enhancement of the approximation convergence rate is attained.Numerical accuracy is much better than that from other spectral element methods.

The blade root flow control is of particular importance to the aerodynamic characteristic of large wind turbines. The paper studies the feasibility of improving blade pneumatic power by applying vortex generators (VGs) to large variable propeller shaft horizontal axis wind turbines, with 2 MW variable propeller shaft horizontal axis wind turbine blades as research object. In the paper, three cases of VGs installation are designed; they are scattered in different chordwise position at the blade root, and then they are calculated, respectively, with CFD method. The results show that VGs installed in the separation line upstream, with the separation line of the blade root as a benchmark, show a better effect. Pneumatic power of blades increases by 0.6% by installing VGs. Although the effect on large wind turbines is not obvious, there is a space for optimization.

The built-in temperature gradient of concrete pavement formed during hardening period caused by various construction conditions will permanently exist in the pavement, which will have significant influence on the service behavior of concrete pavement. However, it’s still not involved in the current Specifications of Cement Concrete Pavement Design for Highway in China. In this paper, a user subroutine based on the ABAQUS code was developed to simulate the effects of weather condition, paving time, curing method, raw material temperature on built-in temperature gradient. The analyses indicate that these factors always produce obvious positive gradient in the slab and the influences of the first three aspects are obvious and the paving temperature of mixture has limited effect on the increasing of the final set temperature gradient. Furthermore, built-in temperature gradient is proposed as an index to evaluate the influences of various construction factors and optimize construction measures.

Aluminum alloy 7A04 compressed at high deformation temperature and large deformation is applied in two different heat treatment (T5 and T6), then microstructure and properties of the alloy after heat treatment are investigated. The mechanical properties are studied by means of the tensile testing and the hardness testing. The microstructure characteristics and the fractorgraphy analysis are respectively investigated with optical microscopy and SEM. The experimental results indicate that after T6 heat treatment, the second-phase particles dispersed in the matrix, which can efficiently improving the strength of the alloy, but reduced the toughness. After T5 heat treatment, the coarse and discontinuous second-phase is distributed along the grain boundary, which can lead to the low strength and high toughness because of the lack of the strengthening phase in the grains. The fracture appearance is intercrystalline fracture after T6 heat treatment, and dimple transgranular fracture after T5 heat treatment.

A long-standing theoretical and practical problem, whether the viscoelasticity can have a measurable and beneficial effect on lubrication performance characteristics, is readdressed in this paper. The upper convected Maxwell model is chosen to study the influence of viscoelasticity on lubricant thin film flows. By employing characteristic lubricant relaxation times in an order of magnitude analysis, a perturbation method is developed for analysing the flow of a Maxwell lubricant between two narrow surfaces. The effect of viscoelasticity on the lubricant velocity and pressure is examined, and the influence of minimum film thickness on lubrication characteristics is investigated. An order of magnitude analysis reveals that the pressure distribution is significantly affected by the presence of fluid viscoelasticity when the minimum film thickness is sufficiently small. This mechanism suggests that viscoelasticity does indeed enhance the lubricant pressure field and produce a beneficial effect on lubrication performance, which is consistent with some experimental observations.

This paper presents the experimental investigation carried out to study the behavior of polypropylene fiber reinforced concrete (PPFRC) under compression and flexure. Crimped polypropylene fibers and twisted polypropylene fiber were used with 0.0%, 0.2%, 0.4% and 0.6% volume fractions. The influence of the volume fraction of each shape of polypropylene fiber on the compressive strength and flexural strength is presented. Empirical equations to predict the effect of polypropylene fiber on compressive and flexural strength of concrete were proposed using linear regression analysis. An increase of 27% in flexural strength was obtained when 0.6% volume fraction of twisted polypropylene fiber was added. It was also found that the contribution of fiber in flexural strength is more effective when twisted fibers were used. The compressive strength was found to be less affected by polypropylene fiber addition.

An analysis of non-Newtonian effects on lubrication flows is presented based on the upper-convected Maxwell constitutive equation, which is the simplest viscoelastic model having a constant viscosity and relaxation time. By employing characteristic lubricant relaxation times in all order of magnitude analysis, a perturbation method is developed to analyze the flow of a non-Newtonian lubricant between two surfaces. The effect of viscoelasticity on the lubricant velocity and pressure fields is examined, and the influence of minimum film thickness on lubrication characteristics is investigated. Numerical simulations show a significant enhancement in the pressure field when the minimum film thickness is sufficiently small. This mechanism suggests that viscoelasticity does indeed produce a beneficial effect on lubrication performance, which is consistent with experimental observations.

This paper developed a new algorithm, which combines the spectral element method with elastic viscous splitting stress method, for viscoelastic fluid in a planar contraction channel. This is an important topic at the cutting edge of research in computational rheology. The technique has been used in some other important rheological flow problems of academic and industrial interest. It provides a bench-mark solution for these viscoelastic flow problems and is currently used in industrial applications including plastic molding and cable coating.

A spectral element method coupled with the elastic viscous split stress technique for computing viscoelastic flows is presented. The rate of deformation tensor is introduced as an additional variable in the momentum equation, but not in the constitutive equation. The nonlinear rheological model, Oldroyd-B, is chosen to simulate the flow of a viscoelastic fluid. Numerical solutions are investigated based on a planar 4:1 abrupt contraction channel flow benchmark problem with different Weissenberg numbers. The results show a good agreement with other numerical predictions.

In dynamically loaded journal bearings it is important to predict and assess the performance of lubricants within the bearing with respect to friction, wear and load bearing capacity over a wide range of operating conditions. In this paper, a mathematical model is described which allows for a systematic study of the effects of shear-thinning, pressure-thickening and temperature-thinning viscosity on the dynamics and stability of a journal bearing. It is also shown that the thermal conductivity of the bearing can have a major effect on the minimum oil film thickness attained in the bearing.

A transient thermal analysis for a dynamic journal bearing system is presented in this paper based on a non-isothermal non-Newtonian fluid model. A spectral element approach is used to solve the full set of coupled equations (kinematics and constitutive) governing the flow of the lubricant, and an operator-splitting spectral element approximation is used to solve the dynamic energy equation. The transient thermal effects in the lubricant viscosity, non-Newtonian lubricant film thickness, variation of the journal rotating speed and time dependent applied load are investigated in this paper. The numerical results indicate that the thermal dynamic analysis plays an important role in the design of the journal bearing systems, especially, under large applied loads and high rotating speeds.

An analysis of journal centre orbits is presented in this paper based on a non-isothermal non-Newtonian fluid model for dynamically loaded bearing systems. A spectral element approach is used to solve a full set of coupled equations (kinematics and constitutive) governing the flow of the lubricant, and an operator-splitting spectral element technique is used to evaluate the dynamic energy equation. The motion of the journal is calculated on the basis of Newtonian mechanics incorporated with a simple cavitation model. The stability of the journal orbits is investigated under a wide range of the rotation speeds of journal. The unstable orbits arise as a sub-harmonic motion when the journal rotation speed is increased beyond a critical value. The influences of the oscillation speeds of the applied loads on the journal orbits are examined. The numerical simulations demonstrate that both the rotation speed of the journal and the oscillation speed of the applied load play an important role in determining the pattern of the journal orbits. The effects of square-wave and rotating applied loads on the journal orbits are also investigated.

The effects of non-Newtonian lubricants on the dynamics of a 3D journal bearing are investigated using a moving spectral element method. Comparisons are made with the findings reported for the 2D case. The variation of L/D, the ratio of the length of the bearing to its diameter, is shown to have a significant effect on the stability properties of the journal. Copyright © 1999 John Wiley & Sons, Ltd.

National Science Foundation of China [11102179, 91230110]; DMU PhD Studentship (De Montfort University, UK); Science Foundation of Institutions of Higher Education of Jiangsu Province, China [11KJB110016]

This paper presents an immersed boundary method for compressible Navier–Stokes equations in irregular domains, based on a local radial basis function approximation. This approach allows one to define a reconstruction of the radial basis functions on each irregular interface cell to treat both the Dirichlet and Neumann boundary conditions accurately on the immersed interfaces. Several numerical examples, including problems with available analytical solutions and the well-documented flow past an airfoil, are presented to test the proposed method. The numerical results demonstrate that the proposed method provides accurate solutions for viscous compressible flows.

Feature Selective Validation (FSV) was incorporated as core component of IEEE Std 1597.1. Recently, discussions have moved from ‘is quantitative comparison of data needed?’ to ‘how can this be applied to multidimensional data?’ The purpose of this paper is to present some of the latest thinking about the key challenges in developing a 1D model to unlimited dimensionality. In particular, the paper will present: (1) a revised mathematical framework for FSV, e.g. using tensor notation to simplify the mathematical representation. (2) A discussion on how the performance of n Dimensional FSV can be verified against human perception. (3) A review on the effects of data that oscillates between positive and negative data points, e.g. transients.

A smoothing technique is developed to calculate the interface conditions of spectral element method for solving the incompressible Newtonian fluid flow. The first derivative at the interface of spectral elements is calculated by using only the adjacent subdomains. Numerical simulations of an incompressible laminar fluid flow through a planar channel and a 2:1 planar contraction channel are presented for various Reynolds numbers.

There are many studies on variations of the Maxwell model. Tichy (1996) discussed an admissible formulation of the Maxwell viscoelastic fluid model using a convected derivative and applied it to two-dimensional lubrication flow. Tichy obtained a solution using a regular perturbation in the Deborah number with the conventional lubrication solution as the leading term. This paper extends Tichy’s model by using a double regular perturbation to the convected Maxwell model. A correspondence solution can also be obtained. Our sliding velocity solution is different from Tichy’s solution; and a modified Reynolds equation is also different from that by Tichy.

A smoothing technique is developed to calculate the interface conditions of spectral element method for solving the incompressible Navier-Stokes equations. The first derivative of spectral element solution at the interface is calculated by using only the adjacent element information. Numerical simulations of an incompressible laminar fluid flow through a 2 : 1 planar contraction channel are presented for various Reynolds numbers.