The primary source of aircraft noise is the fan noise from the engines; natural approaches to reducing this noise involve acoustic shape optimization of the inlet and impedance optimization of the liner. This project will use optimal control to systematically determine the inlet shape and the linear material impedance factor that minimize the fan noise. A novel feature of this approach is that ...

This article presents the results of a numerical study, using computational fluid dynamics (CFD) analysis to investigate the species distribution of proton exchange membrane fuel cells (PEMFCs) with deflected membrane electrode assembly (MEA). These new geometry were examined while employing three-dimensional, single phase, non-isothermal and parallel flow for model of a PEM fuel cell. This num...

This paper considers tbe rearrangement process in the twostage btoadcast switching network presented by F. IC. Hwang and G . W. Richards in IEEE TRANSACTIONS ON COMMUNICATIONS, October 1985. By defining a certain function it is possible to calculate an upper bound on the number bf connections to be moved during a rearrangement. When each inlet channel appears twice, the maximum number of connec...

On many occasions, fan or compressor stages have to face azimuthal flow distortion at inlet, which affects their performance and stability. These distortions can be caused by external events some particular geometrical features. The aim of this work is propose a joined numerical experimental analysis the behavior in single axial stage under distortion. are generated different grids that placed ...

This paper illustrates the mechanism of U-shaped vortex formation which is found both by experiment and DNS. The main goal of this paper is to explain how the U-shaped vortex is formed and further develops. According to the results obtained by our direct numerical simulation with high order accuracy, the U-shaped vortex is part of the coherent vortex structure and is actually the tertiary strea...

this paper studied the mathematical method of flow with regard to two-phase boundary layer that created over the iced surface. based on experimental results, skin drag over the iced surface compared with this force that compute with slip condition. based on this results, for iced surface blasius equation solving at non-slip condition, can replace with solving the blasius equation with slip cond...

NASA has been studying future transport concepts, envisioned to be technically realizable in the timeframe of 20202030, to meet environmental and performance goals. One concept receiving considerable interest involves a propulsion system embedded into a hybrid wingbody aircraft. While offering significant advantages in fuel savings and noise reduction by this concept, there are several technica...

In this paper we study the stability of finite difference approximations to initial-boundary hyperbolic systems. As is well-known, a proper specification of boundary conditions for such systems is essential for their solutions to be well-defined. We prove a discrete analogue of the above if the numerical boundary conditions are consistent with an inflow part of the problem, they render the over...