With the ever rising need for better fuel efficiency and lower emissions, the development of better engine technology is essential. Different strategies are being considered to increase engine efficiency, such as direct injection or downsizing. Certain regimes are clearly identified as optimal for certain range of loads. For gasoline engines, the Homogeneous Charge Compression Ignition (HCCI) c...

Large-eddy simulation (LES) is commonly used in atmospheric simulations when the domain size is small enough to allow grid spacing that resolves turbulence. At these resolutions LES is more accurate than the Reynolds-averaged Navier-Stokes (RANS) models used for mesoscale simulations, but far less computationally intensive than direct numerical simulation (DNS). Grid nesting, used to transfer t...

Submit Manuscript | http://medcraveonline.com Space Agency; MELOS: Mars Exploration with Lander-Orbiter Synergy; JAXA: Japan Aerospace Exploration Agency; ARES: Aerial Regional-scale Environmental Survey; L/D: Lift-to-Drag Ratio; LES: Large-Eddy Simulations; DNS: Direct Numerical Simulation; MABE: Mars Airplane Balloon Experiment; RANS: Reynolds Averaged Navier-Stokes; CFRP: Carbon Fiber-Reinfo...

Wall-modeled large-eddy simulation is applied to a transonic axial compressor rotor (NASA Rotor 37). The simulation results show a significant improvement over fully turbulent RANS in the prediction of the overall performance, mainly by capturing boundary layer transition on the blade. Sensitivity of the result to the end-wall boundary conditions (isothermal/adiabatic walls) and the inflow prof...

In order to estimate Reynolds number effects on a transonic transport aircraft CFD calculations have been performed. The CFD calculations have been done solving the RANS equations on an unstructured grid for varying Reynolds number at transonic conditions. Low Reynolds number data have been extrapolated to a higher Reynolds number condition with different scaling methodologies in order to evalu...

One of the most interesting problems in fluid dynamics is the prediction of particleladen turbulent flows. These flows are as diverse as pollutant dispersion in the atmosphere and contaminant transport in industrial applications. An issue of primary importance for moderately dense suspensions concerns how particles affect the turbulent flow itself, the so-called two-way coupling. It is known th...

Recommendations on the proper use of CFD for the prediction of pedestrian winds are presented. They are restricted to statistically steady turbulent flows modelled by the RANS equations and based on a comprehensive literature review. Furthermore, only aspects of the boundary conditions and the numerical parameters which influence the accuracy of the solutions are addressed.