A new method for reducing large-scale mixing noise from dual-stream jets is presented. The principle is reduction of the convective Mach number of turbulent eddies that produce intense downward sound radiation. In a jet representing the coaxial exhaust of a turbofan engine, this is achieved by tilting downward, by a few degrees, the bypass (secondary) plume relative to the core (primary) plume....

Physics of Failure models are mathematically derived, deterministic models based on knowledge of failure mechanisms and the root causes of failures. Failure rates are predicted based on stresses, material properties, individual use and environmental conditions. Fixed Vanes are primarily used in fluid machines (turbines, pumps, and windmills etc.) and in aircraft (control surfaces) apart from a ...

Numerical simulations were performed to investigate pressure fluctuations in the S-shaped region of a pump-turbine model. Analyses focused on pressure fluctuations in the draft tube and in the gap between the guide vanes and runner. Calculations were made under six different operating conditions with a constant guide vane opening, and the best efficiency point, runaway point, and low-discharge ...

In this paper, we propose an experimental and computational model to challenge the dynamic body boundary problem, as seen in the rubber hands illusion and phantom limbs. Our strategy examines an agent‟s “attention shift”. A computational model (Iizuka & Ikegami, 2005) was used to explore how a body and sensor can be made inseparable. A model agent was required to determine the number of vanes o...

Abstract Bird feathers sustain bending and vibrations during flight. Such unwanted could potentially cause noise flight instabilities. Damping alter the system response, resulting in improving quiet flight, stability, controllability. Vanes of are known to be indispensable for supporting aerodynamic function wings. The relationship between hierarchical structures vanes mechanical properties fea...

The performance of a diffuser in a pump stage depends on its configuration and placement within the stage. The influence of vane shape on the hydrodynamic performance of a diffuser has been studied. The goal of this effort has been to improve the performance of a pump stage by optimizing the shape of the diffuser vanes. The shape of the vanes was defined using Bezier curves and circular arcs. S...

The spitting cobra Naja pallida can eject its venom towards an offender from a distance of up to two meters. The aim of this study was to understand the mechanisms responsible for the relatively large distance covered by the venom jet although the venom channel is only of micro-scale. Therefore, we analysed factors that influence secondary flow and pressure drop in the venom channel, which incl...

Although the mathematics that define the operation of an impeller can be complex (it is the stuff of Bernoulli and Euler), its purpose is straight forward. An impeller is designed to impart energy to a fluid so that it will flow or, if it is already flowing, undergo some increase in its elevation or pressure. It accomplishes this by increasing the fluid’s velocity as it travels through its vane...

This paper focuses on the design of a cascade within a cold stream thrust reverser during the early, conceptual stage of the product development process. A reliable procedure is developed for the exchange of geometric and load data between a two dimensional aerodynamic model and a three dimensional structural model. Aerodynamic and structural simulations are carried out using realistic operatin...

The flow hydrodynamics in a low specific speed radial pump-turbine reduced scale model is experimentally investigated under off-design operating conditions in generating mode. Wall pressure measurements, in the stator, synchronized with high-speed flow visualizations in the vaneless space between the impeller and the guide vanes using air bubbles injection are performed. When starting from the ...