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Wind energy is more and more used as a renewable energy source character. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... The present turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be modeled by unsteady calculation. One of the main problems of such geometry is to simulate the two combined...
The drag of an isolated rotating wheel sub-system including its accessories (tire, suspension, A-arms and fender) of a tricycle vehicle was studied numerically using the Star CCM+. The purpose of the present work is to optimize the wheel subsystem through drag analysis. The numerical model is validated by comparison to the wind tunnel experimental drag and pressure coefficient. Two aerodynamic shapes of A-arms are designed to perform drag reduction. Numerical simulations show a sensitive drag decrease up to 19.9% of the original wheel subsystem.
Principles of RANSE-based (Reynolds Averaged Navier-Stokes Equations) numerical modelling of a fl ow around the tanker model hull are introduced with the application of the CD-adapco STAR-CCM+ (Computational Continuum Mechanics) software package in the fi eld of ship hydrodynamics. The numerical model used in simulation is drawn up through base parameters and methods of geometrical and mathematical modelling. Results of two numerical simulations performed at design and ballast loading conditions are presented and a comparison with available experimental data is made. Some aspects of further...
Computational Fluid Dynamics (CFD) is becoming a widely used complement to towing tank tests in order to predict the resistance and the wake field during the design phase of a ship. In addition, a lot of research is done on developing valid and effective models for simulating self propulsion and manoeuvring with an operational propeller and ruder configuration. The purpose of this project is to make reliable CFD calculation of the flow arounf the stern and particularly the inflow of the propeller disc (the wake) for a given ship in model scale. The results will be compared with towing tank...
The objective of the present work is to investigate numerically the 3D flow within diesel injector-like geometry using a cavitation model implemented in a commercial CFD code. A comprehensive study of various numerical parameters is performed which can subsequently be used to simulate cavitation under realistic diesel engine conditions.Numerical predictions were performed on a throttle channel at different operating conditions, with and without cavitation , and compared to available experimental measurements. Overall , it was found that the cavitation model was able to predict the onset of...
A RANS based computational fluid dynamics method incorporating the free-surface Volume of Fluid (VOF) multiphase flow has been employed to compute the resistance forces of two idealized seatrain concepts for fixed flotation as well as for two degrees of freedom (DOF) independent motion of each unit. The motion of each unit is analyzed using Dynamic Fluid Body Interaction (DFBI) morphing mesh technique. Seatrain, a series of hulls connected with rigid (except for pitch and heave) links is a potentially valuable concept for the Army Sealift, the Marine Corps as well as a broad spectrum of...
Unstructured grid generators are becoming more popular among engineers, due to the significant amount of time that can be saved by using them. They provide a great flexibility in the treatment of any kind of geometry, with minimal interaction from the user. However, it is important that the user selects an appropriate cell shape from the list of available cell topologies supported by the simulation tool. This important choice depends on a combination of flow physics, available computational resources and the complexity of the geometry. Applying a proper mesh configuration to CFD simulations...
In this study a semi-reduced reaction scheme developed previously was used to derive a 26 step reduced mechanism, using the sensitivity approach and the steady state approximation (QSS) with Chemkin code. This 26 step model has been implemented in a CFD combustion code (STAR-CD/Kinetics) to study combustion process in homogeneous charge compression ignition (HCCI) engines. The first results obtained have confirmed the very rapid combustion phase and fast heat release with completely homogeneous mixtures, for a wide range of operating conditions. This numerical approach has been used first to...
The objective of the present investigations was to identify the fundamental aerodynamic issues of residential wind-power systems based on rooftop wind panels with horizontal rotors. Numerical investigations were performed for (a) a single high efficiency wind turbine placed in a cross flow, (b) a model roof-top placed in a cross flow, and finally, after the identification of the optimum roof-top location for placing the wind turbine, (c) simulations of the roof-top panel with multiple horizontal rotors. Numerical results are presented for two cases of wind turbine blades being aligned or at...

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