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The work investigates the pressure waves behavior in a cavity, the way that the treatment with Finite Volumes Method can be understood, aiming future studies like pressure waves in air intake system of an internal combustion engine. Using a CFD code it is possible to analyze more complex systems, including three dimensional effects. In most of cases, the problem is solved using analytical methods or one-dimensional numerical method. In the present work, the governing equations was discretized by Finite Volumes Method with an explicit formulation, and the time integration was made using the...
Vertical-axis wind turbines (VAWTs) have been shown to be useful machines to extract energy from the wind. It allows a large scale of power energy which can be extracted from small scale applications through to large scale electricity production. The present study concerns small scale applications. Some inventors discovered this kind of turbine in the same time on different places (in France, in Australia…) these last ten years. This paper concerns an industrial one used to light publicity panel but it can be also used to light small areas like parking, roads or for water pumping for example...
In water supply installations, noise pollution often occurs. As a basic component of a system, a flush valve may frequently be a source of noise and vibration, of which cavitation can be the problem, especially during valve closing or valve opening. The aim of this paper is to show how a numerical industrial code can point out a cavitation problem even if this code doesn’t use a cavitation model. This approach shows a good agreement with one using a cavitation model. The numerically obtained contours of the volume fraction of water vapour show cavitation inception distribution behind the...
Distributions in reactant species concentration in a PEMFC cause distributions in local current density, temperature and water over the area of a PEMFC. These can lead to effects such as flooding or drying of the membrane and cause stresses in different regions of the fuel cell. Changing flow-field configuration, including channel path length, width, or height to distribute the gas more evenly, is one method of minimizing these stresses. This work numerically investigated how serpentine flow-fields with different channel/rib's cross section areas affect performance and species distributions...
The discovery and archaeological excavation of the “Nossa Senhora dos Martires” wreck in the Tagus river between 1996 and 2001 renewed the interest in studying the ships (naus) that were used for transporting people and goods between Portugal and India in 16th and 17th centuries. A reconstruction of the hull, including above waterline structures, of the masts, yards and sail plan was carried out using the archaeological data, contemporary documents and iconography. In the present paper, the aerodynamics of the sails of the nau is numerically simulated. The reconstructed model of the nau is...
The rapid advancement of numerical techniques and the availability of increasingly powerful supercomputers recently enabled scientists to use large eddy simulation (LES) to simulate numerically the flow in a full subassembly composed of wire-wrapped pins. Because of the extreme computational cost of such simulations, it was not possible to conduct a sensitivity case on the pin-wire interface modeling. Since such calculations are likely to be extended to conjugate heat transfer, however, a sensitivity study is necessary to assess the reliability of the numerical results. It is well known, for...
Large-eddy simulation (LES) was used to study the influence and the resulting flow mechanisms of active flow control applied to a two-dimensional vehicle geometry. The LES results were validated against existing Particle Image Velocimetry (PIV) and force measurement data. This was followed by an exploration of the influence of flow actuation on the near-wake flow and resulting aerodynamic forces. Not only was good agreement found with the previous experimental study, but new knowledge was gained in the form of a complex interaction of the actuation with the coherent flow structures. The...
Thermo-mechanical simulation of the friction stir butt welding (FSBW) process was performed for AA5083-H18 sheets, utilizing a commercial finite volume method (FVM) code, STAR-CCM+, which is based on the Eulerian formulation. Distributions of temperature and strain rate histories were calculated under the steady state condition and simulated temperature distributions (profiles and peak values) were compared with experiments. It was found that including proper thermal boundary condition for the backing plate (anvil) is critical for accurate simulation results. Based on the simulation, thermal...
International attention has been considerably paid for the technology of CO2 capture and storage (CCS) these days because of global warming. In line with the fact that carbon dioxide capture and storage (CCS) technology has been regarded as one of the most promising option to mitigate the climate change and global warming, we have started a 10-year R&D project on CO2 storage in marine geological structure. We carried out relevant studies, which cover the initial survey of potentially suitable marine geological structure for CO2 storage site, monitoring of the stored CO2 behavior, basic...
There are several important considerations in the design of a suction supply sump. It is imperative that the amount of turbulence and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices may reduce pump performances, have large effects on the operating conditions and lead to increase plant operating costs. Experiments, conducted in order to select best positions of the suction pipe of a water-intake sump, show qualitative results concerning flow disturbances in the pump-intake...

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