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Multiphysics problems are solved either with monolithic or segregated approaches. For accomplishing contrary discretisation requirements of the physics, disparate meshes are essential. This paper is comparing experimental results of different interpolation methods for a segregated coupling with monolithic approaches, implemented using a global and a local nearest neighbour method. The results show the significant influence of discretisation for multiphysics simulation.

Applying disparate meshes to the monolithic as well as the segregated calculation of finite element problems and evaluating the related numerical error is content of the contribution. This is done by an experimental evaluation of a source and a material coupling applied to a multiphysics problem. After an introduction to the topic, the evaluated multiphysics model is described based on two bidirectional coupled problems and its finite element representation. Afterwards, the considered methods for approximating the coupling are introduced. Then, the evaluated methods are described and the experimental results are discussed. A summary concludes this work.

An experimental evaluation of the numerical errors for different multiphysics coupling methods using disparate meshes is presented based on a bidirectional electro-thermal simulation. Different methods approximating the coupling values are introduced and challenges of applying these methods are given. It is also shown, that the approximation of the coupling integrals is expensive. Arguments for applying the different methods to the monolithic and the segregated solution strategies are given and applied on the example. The significant influence of the mesh density within the coupled meshes is shown. Since the projection and the interpolation methods do influence the result, a careful decision is advised.

In this contribution, existing coupling methods are described, applied and compared on their application for coupling disparate meshes within a multiphysics simulation. Knowing their performance is relevant when deciding for a monolithic or a segregated calculation approach with respect to physics dependent contrary discretisation requirements. To the authors’ knowledge, it is the first time these methods are compared with a focus on an application in multiphysics simulations and experimental results are discussed.

The purpose of this paper is to simulate two macrosegregation benchmarks with a newly developed stabilized finite element algorithm based on a semi-implicit pressure correction scheme.

A streamline-upwind/Petrov–Galerkin (SUPG) stabilized finite element algorithm is developed for the coupled conservation equations of mass, momentum, energy and species. A semi-implicit pressure correction method combined with SUPG stabilization technique is proposed to solve the convection flow during solidification. An analytically derived enthalpy method is adopted to solve the energy conservation equation. The nonlinearities of the energy and species equations are tackled by Newton–Raphson method. Two macrosegregation benchmarks considering the solidification of an Al-4.5 per cent Cu alloy and a Sn-10 per cent Pb alloy are simulated.

A very good agreement is achieved by comparison with the classical finite volume method and a novel meshless method for the Al-4.5 per cent Cu alloy solidification benchmark. Moreover, a unique reference numerical solution has been obtained. Besides, it is demonstrated that the stabilized finite element algorithm can capture the flow instability and channel segregation during solidification of the Sn-10 per cent Pb alloy.

A semi-implicit pressure correction method combined with SUPG stabilization technique is adopted to develop robust stabilized finite element algorithm for the macrosegregation model. A new enthalpy formulation for heat transfer problems with phase change is derived analytically.

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.

The contribution of the built environment within communities plays a significant role in the higher rates of childhood obesity, particularly among black and Hispanic youth. The purpose of this paper is to investigate neighborhood assets and barriers to nutrition and physical activity in an underserved, majority-minority suburban community in New York State, USA using Photovoice, a community-based participatory research method.

Nine local youth took photographs to visually identify the community’s environmental assets and barriers. Through an extensive review and selection of photos and group discussion themes were identified. Final results of the Photovoice project were presented to local policy makers and community members for action.

Participants provided complex and insightful perspectives of health inequalities in the suburbs, including limited access to fresh, healthy food, and safe spaces for physical activity. They also understood that improving nutrition and physical activity practices required policy changes and civic engagement.

This study represented one suburban area of New York, and is not meant to be representative of all suburban areas. However, the findings of environmental barriers to childhood obesity are similar to those found in urban areas, suggesting similarities in low-income communities of color.

This study suggests that Photovoice is an effective way of collaborating between various community stakeholders (particularly youth) in an underserved suburb that can result in community changes.

Besides achieving all three Photovoice goals – recording and reflection, dialogue, and reaching policymakers – the Photovoice project identified a long-standing environmental hazard as a result of the partnerships established between the youth, academic institution, community-based organizations, and residents. This study also identified factors in the built environment that contribute to health disparities in a racially segregated suburban community.

Presents a quasi three‐dimensional formulation for filling a thin section cavity which is derived under the assumption that no transverse flow occurs in the gap. A no‐slip condition was applied on all surfaces occupied by the fluid and a slip condition on all air‐filled (empty) surfaces. The formulation was developed to analyse the sections which lie in the xy‐plane or may be oriented arbitrarily in three‐dimensional space. Solves the discretized thickness‐integrated finite element flow equations by using the implicit mixed velocity‐pressure formulation, and uses the volume of fluid (VOF) method to track the free surfaces. Presents numerical examples which confirm the accuracy of the formulation and demonstrate how it can be used to model the filling of planar and three‐dimensional thin section cavities of irregular shape.

To show the effect of radiation from the heat source and the variation of fluid properties on the laminar natural convection induced by a line heat source.

The governing equations – Navier‐Stokes and energy equation are discretized in a staggered grid by a control volume approach, and they are solved using a segregated technique. The equations for the fluid and solid (line heat source) phases are solved simultaneously. The three sides of the computational domain are open boundary. Some of the physical and thermo‐physical properties of the fluid (air) such as density, thermal conductivity and viscosity were considered to vary with temperature.

The present predictions are compared with those using the Boussinesq approximation, with the results for the boundary layer equations, and with the experimental results. The present predictions reveal considerable departure from the Boussinesq‐based solution and from the boundary layer results. This study also shows the radiation exchange between the heat source and surrounding has major effect in the results. Thus, the departure between the experimental and analytical results can be explained by the effect of radiation exchange.

In this work, just studied steady‐state laminar thermal plume with the effects of radiation from heat source and the variation of air properties with temperature while it is propose to extend this work to transient and/or turbulent flow.

The effect of radiation from a line heat source on the flow filed around the source and offers enhancement of design to thermal engineers.

This paper presents a unified numerical method able to address a wide class of fluid flow problems of engineering interest. Arbitrary fluids are treated specifying totally arbitrary equations of state, either in analytical form or through look‐up tables. The most general system of the unsteady Navier–Stokes equations is integrated with a coupled implicit preconditioned method. The method can stand infinite CFL number and shows the efficiency of a quasi‐Newton method independent of the multi‐block partitioning on parallel machines. Computed test cases ranging from inviscid hydrodynamics, to natural convection loops of liquid metals, and to supersonic gasdynamics, show a solution efficiency independent of the class of fluid flow problem.

Stir casting is a promising technique used for the manufacture of Al-SiC metal matrix composites. The clustering of reinforcement particles is a serious concern in this production method. In this work, mushy-state solidification characteristics in stir casting are numerically simulated using computational fluid dynamics techniques to study the clustering of reinforcement particles.

Effects of process parameters on the distribution of particles are examined by varying stirrer speed, volume fraction of reinforcement, number of blades on stirrer and diameter ratio (ratio of crucible diameter to stirrer diameter). Further, investigation of characteristics of cooling curves during solidification process is carried out. Volume of fluid method in conjunction with a solidification model is used to simulate the multi-phase fluid flow during the mushy-state solidification. Solidification patterns thus obtained clearly indicate a strong influence of process parameters on the distribution of reinforcement particles and solidification time.

From the simulation study, it is observed that increase in stirrer speed from 50 to 150 rad/s promotes faster solidification rate. But, beyond 100 rad/s, stirrer speed limit, clustering of reinforcement particles is observed. The clustering of reinforcement particles is seen when volume fraction of reinforcement is increased beyond 10 per cent. When number of blades on stirrer are increased from three to five, an increase in solidification rate is observed, and an uneven distribution of reinforcement particles are observed for five-blade geometry. It is also seen from the simulation study that a four-blade stirrer gives a better distribution of reinforcement in the molten metal. Decrease in diameter ratio from 2.5 to 1.5 promotes faster solidification rate.

There is 90 per cent closeness in results for simulation study and the published experimental results.

The purpose of this paper is to describe the use of computational fluid dynamics (CFD) to simulate indoor radon distribution and ventilation effects. This technique was used to predict and visualize radon content and indoor air quality in a one‐family detached house in Stockholm. The effects of intake fans, exhaust fans and doors on radon concentration were investigated.

In this study a mechanically balanced ventilation system and a continuous radon monitor (CRM) were used to measure the indoor ventilation rate and radon levels. In a numerical approach, the FLUENT CFD package was used to simulate radon entry into the building and ventilation effects.

Results of the numerical study indicated that indoor pressure created by ventilation systems and infiltration through doors or windows have significant effects on indoor radon content. The location of vents was found to affect the indoor radon level and distribution.

It may be possible to improve any discrepancies found in this article by using a more refined representation of grids and certain boundary conditions, such as pressure and temperature differences between inside and outside and by considering some real situations in residential buildings and external situations.

From the viewpoints of indoor air quality (IAQ) and energy savings, ventilation has two opposing functions; on the positive side it enhances IAQ and the establishment of thermal comfort, and on the negative side it increases energy consumption. This paper describes the search for a solution to cope with this contradiction.

The purpose of this paper is to show the superior turbulence method in CFD analysis of radial turbo machines and to introduce the best way to choose turbulence parameters whenever FLUENT user applies this software as a complementary design tool for high‐speed turbo machinery components.

One of the most important issues in CFD is analysis of flow field in turbo machines. Flow in high‐speed radial turbo machinery is a 3D, turbulent and unsteady behavior so needs suitable method for converging. It is clear that the turbulence model has an extraordinary effect on investigation of 3D flows in high‐speed turbo machinery. A centrifugal compressor of micro and radial turbines have been designed and simulated 3D using the commercial CFD‐code FLUENT 6. Three turbulence models k‐ε/standard, renormalization‐group (RNG) and RSM were considered and results of three models were compared with experimental and 1D design results.

The study showed numerical results are compatible with experimental performance data. It determined that RNG method in CFD analysis of radial turbo machines has provided better results than the standard k‐ε method. In addition, when using the RNG method, the phenomena of flow field were more visible than other methods.

This paper offers use of the RNG method as a superior turbulence method in CFD analysis of radial turbo machines.