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This paper aims to verify the inhibition of the hydrogen permeation effect of the coating and to quantitatively and qualitatively characterize the coating-induced stress.

By means of slow strain rate tensile testing (SSRT) in humid air, thickness measurement, fracture morphology, cross-section morphology and surface morphology, hydrogen content measurements, flow stress difference method.

The results demonstrate that the mechanism of the inhibition of hydrogen embrittlement by the coating is mainly attributed to the repression of hydrogen permeation and the additional coating-induced compressive stress.

It is proven that the micro-arc oxidation (MAO) coating does inhibit hydrogen entry into the alloy, and the stress induced by the MAO coating is compressive stress, which can restrain the hydrogen embrittlement of the alloy. Therefore, the mechanism of the inhibition of hydrogen embrittlement is dominated by the mechanisms of both hydrogen permeation inhibition and coating-induced stress.

The purpose of this paper is to study flap application in the airfoil comprising a cross flow fan by experiment and numerical simulation.

An airfoil was made and tested in a blowing wind tunnel. Because of complicated shape of the airfoil, distributed quantities in the flow field cannot be measured. They were computed by establishing a CFD code validated by the experimental data. The k‐ε model was used for the Reynolds stress modeling. Flow was considered incompressible, two dimensional and steady‐state. The pressure‐velocity coupling was performed by the SIMPLEC algorithm and convection terms were discretized by using the second‐order upwind discretization scheme.

Computed aerodynamic coefficients were in good agreement with the experimental results. Flap augmented lift and pitching moment coefficients of the airfoil considerably. It was perceived that the airfoil aerodynamic coefficients decrease with the Reynolds number, its lift and pitching moment coefficients increase and its drag coefficient decreases with the fan speed. Static pressure difference between the airfoil surfaces increased with the flap angle and consequently at higher flap angles it must have larger aerodynamic coefficients as proved by the experiments. This pressure difference increases with the Reynolds number that is equivalent to higher aerodynamic forces. It was shown by the numerical solution that surface pressure on the airfoil upper wall decreases with the fan speed while it is not sensitive to the fan speed on the airfoil bottom wall.

This is the first instance in which flap application in the airfoil with forced airflow provided by an integrated cross flow fan is studied.

The purpose of this paper is to propose a progressive inverse identification algorithm to characterize flow stress of tubular materials from the material response, independent of choosing an a priori hardening constitutive model.

In contrast to the conventional forward flow stress identification methods, the flow stress is characterized by a multi-linear curve rather than a limited number of hardening model parameters. The proposed algorithm optimizes the slopes and lengths of the curve increments simultaneously. The objective of the optimization is that the finite element (FE) simulation response of the test estimates the material response within a predefined accuracy.

The authors employ the algorithm to identify flow stress of a 304 stainless steel tube in a tube bulge test as an example to illustrate application of the algorithm. Comparing response of the FE simulation using the obtained flow stress with the material response shows that the method can accurately determine the flow stress of the tube.

The obtained flow stress can be employed for more accurate FE simulation of the metal forming processes as the material behaviour can be characterized in a similar state of stress as the target metal forming process. Moreover, since there is no need for a priori choosing the hardening model, there is no risk for choosing an improper hardening model, which in turn facilitates solving the inverse problem.

The proposed algorithm is more efficient than the conventional inverse flow stress identification methods. In the latter, each attempt to select a more accurate hardening model, if it is available, result in constructing an entirely new inverse problem. However, this problem is avoided in the proposed algorithm.

This paper examines various turbulence models for numerical simulation of a steady, two-dimensional (2-D) plane wall jet without co-flow using the commercial CFD software (ANSYS FLUENT 14.5). The purpose of this paper is to decide the most suitable and most economical method for steady, 2-D plane wall jet simulation.

Seven Reynolds-averaged Navier–Stokes (RANS) turbulence models were evaluated with respect to typical jet scaling parameters such as the jet half-height and the decay of maximum jet velocity, as well as coefficients from the law of the wall and for skin friction. Then, a plane wall jet generating from a rectangular slot of 1:6 aspect ratio located adjacent to the wall was investigated in a three-dimensional (3-D) model using large eddy simulation (LES) and the Stress-omega Reynolds stress model (SWRSM), with the results compared to experimental measurements.

The comparisons of these simulated flow characteristics indicated that the SWRSM was the best of the seven RANS models for simulating the turbulent wall jet. When scaled with outer variables, LES and SWRSM gave generally indistinguishable mean velocity profiles. However, SWRSM performed better for near-wall mean velocity profiles when scaled with inner variables. In general, the results show that LES performed reasonably well when predicting the Reynolds stresses.

The main contribution of this article is in determining the capabilities of different RANS turbulence closures and LES for the prediction of the 2-D steady wall jet flow to identify the best modelling approach.

The purpose of the paper is to explore the application of radio frequency identification (RFID) to improve traceability in a flow of granular products and to illustrate examples of special issues that need to be considered when using the RFID technique in a process industry setting.

The paper outlines a case study at a Swedish mining company, including experiments to test the suitability of RFID to trace iron ore pellets (a granular product) in parts of the distribution chain.

The results show that the RFID technique can be used to improve traceability in granular product flows. A number of special issues concerning the use of RFID in process industries are also highlighted, for example, the problems to control the orientation of the transponder in the read area and the risk of product contamination in the supply chain.

Even though only a single case has been studied, the results are of a general interest for industries that have granular product flows. However, future research in other industries should be performed to validate the results.

The application of RFID described in this paper makes it possible to increase productivity and product quality by improving traceability in product flows where traceability normally is problematic.

Prior research has mainly focused on RFID applications in discontinuous processes. By contrast, this paper presents a novel application of the RFID technique in a continuous process together with specific issues connected to the use of RFID.

A finite element based numerical model is employed to obtain isothermal and heat transfer predictions for the case of turbulent flow with a decaying swirl component in a stationary circular pipe. An assessment is made on the quality of predictions based on the choice of turbulence modelling technique adopted to close the governing equations. In the present work the one‐equation, two‐equation and algebraic Reynolds stress turbulence models are employed. For the confined flow problem investigated, accurate prediction of the near‐wall conditions is essential. This is particularly the case for confined swirling flow where the variation of variables near the wall is often somewhat greater than encountered in pure axial flow. A finite element based near‐wall model is employed as an alternative to conventional techniques such as the use of the standard logarithmic functions. Of significance is the fact that flow predictions based on the use of the unidimensional finite element techniques are closer to experiment compared to the wall function based solutions for a given turbulence model. As expected, improvements in the flow predictions directly contribute to improved simulation of the thermal aspects of the problem.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

The purpose of this paper is to present a full three-dimensional (3D) computational fluid dynamics (CFD) analysis of a rectangular asymmetric 3D diffuser utilizing seven turbulence models frequently used in engineering to assess the predictive capabilities of the turbulence models for separated flows in internal flows.

The structured computational grids are generated by means of the mesh generation tool IGG software package. The computational grids are imported into the commercial CFD code Fluent. The performance of the different turbulence models adopted has been systematically assessed by comparing the numerical results with the available experimental and direct numerical simulation/large eddy simulations data.

The comparisons show that the Reynolds stress model (RSM) evidently performs better than the other turbulence models for predicting wall pressure, velocity, and vorticity fields. Moreover, only the RSM can predict the separation bubble region around the top right corner, which is consistent with the experiment. It is found that the RSM can well predict Prandtl’s secondary flow of the second kind for considering turbulence anisotropy, whereas the other models cannot.

The paper utilizes seven turbulence models frequently used in engineering in detailed numerical investigations of a real 3D diffuser to expand the scope of application for various turbulence models. The studies are valuable for the proper use of the turbulence models, allowing the designers to understand the numerical results further and contributing to the modification of the turbulence models for 3D flows.

The purpose of this article is to present numerical investigations of flow control with piezoelectric actuators on a backward facing step (BFS) and fluidic vortex generators on a NACA0015 aerofoil for the reattachment and separation control through the manipulation of the Reynolds stresses.

The unsteady flow phenomena associated with both devices are simulated using Spalart–Allmaras-based hybrid Reynolds averaged Navier-Stokes (RANS)/large eddy simulation (LES) models (detached eddy simulation (DES), delayed detached eddy simulation (DDES) and improved delayed detached eddy simulation (IDDES)), using an in-house computational fluid dynamics (CFD) solver. Results from these computations are compared with experimental observations, enabling their reliable assessment through the detailed investigation of the Reynolds stresses and also the separation and reattachment.

All the hybrid RANS/LES methods investigated in this article predict reasonable results for the BFS case, while only IDDES captures the separation point as measured in the experiments. The oscillating surface flow control method by piezoelectric actuators applied to the BFS case demonstrates that the Reynolds stresses in the controlled case decrease, and that a slightly nearer reattachment is achieved for the given actuation. The fluidic vortex generators on the surface of the NACA0015 case force the separated flow to fully reattach on the wing. Although skin friction is increased, there is a significant decrease in Reynolds stresses and an increase in lift to drag ratio.

The value of this article lies in the assessment of the hybrid RANS/LES models in terms of separation and reattachment for the cases of the backward-facing step and NACA0015 wing, and their further application in active flow control.

The purpose of this paper is to investigate flow behavior of electrorheological (ER) fluid in a closed piston–cylinder system.

A basic study of flow characteristics of ER fluid in a damper model is conducted experimentally and numerically. The electric field is applied between inner wall of the cylinder and outer wall of the piston, and the pressure difference between upper and lower chamber of the cylinder is measured. A numerical prediction of ER fluid flow in the damper model system is performed in order to study the ER fluid flow characteristics. Visualization experiment is also made and used to qualitatively verify the numerical formulation.

The agreement between the numerical predictions and experimental results is encouraging, and the ER fluid flow patterns under different piston aspect ratios, movement speeds and applied electric field strengths are presented. The results show that the piston aspect ratio has much smaller influence on the ER flow pattern than other influencing factors. Increasing piston movement speed or reducing the electric field applied is helpful to reduce the pressure response time period, which is an important indicator showing sensitiveness of the damper. It is also seen that the pressure difference between the upper and lower chamber of the cylinder increases with the electric field strength and the piston movement speed.

First time the detailed investigation into the hydrodynamics behavior in such working models of engineering applications for ER fluid.