Experimental Study and Computational Simulation for Shock Characteristics Estimation of Okinawa’s Soils “Jahgaru”

A Belleville washer can be best described as a non flat washer with a conical shape and a uniform cross section. They are also known as disk springs and as the name suggests they are often utilised for their load bearing capabilities. Due to their compactness along the axis of loading and a wide range of attainable load-deflection characteristics they are an attractive alternative to conventional springs. Though Belleville washers are primarily used for their load bearing capabilities, they can also be used to build a damping device; which in turn can be used as part of a suspension system. The non linear deflection of the spring makes it difficult to predict the resulting pressure-flow characteristic and as a result the damper pack is built either by an experienced operative or by a trial and improvement method. Without an analytical tool to predict the behaviour a designer cannot exploit the full functionality of this type of spring. The intension of this paper is to present research undertaken to develop a correlation which describes the pressure drop required for various flow rates when using Belleville washers as damping elements. Using existing load-deflection theory an initial model was developed to relate load with pressure and deflection with flow area which could be used to estimate flow rate. The solutions from a computer simulation showed similar trends to those found in the experimental study, but they estimated smaller pressure drops for a given flow rate. It was postulated that the exit velocity of the fluid created a region of low pressure which tended to close the opening and thus increase the pressure drop. This hypothesis was examined and confirmed with a computational fluid dynamic simulation and the results were used to modify the existing model. Analysis of the new model showed good agreement with the experimental study.

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Flow features around double cones at hypersonic speed

The Aeronautical Journal ◽

10.1017/s000192400000840x ◽

2013 ◽

Vol 117 (1193) ◽

pp. 741-748

Author(s):

R. Gomes-Fernandes

Keyword(s):

Experimental Study ◽

Numerical Solution ◽

Steady Flow ◽

Hypersonic Flow ◽

Simulation Study ◽

Additional Data ◽

Computational Simulation ◽

Hypersonic Speed ◽

Flow Features ◽

Shock Oscillation

AbstractAn experimental study of double cone geometries in hypersonic flow (at M∞of 8·2 and Redof 0·36 × 106) was performed to provide additional data to a computational simulation study. In this study, depending on how the flow was initialised, the numerical solution yielded a violent pulsation mode of instability or a steady flow. Finally, an analysis of the shock oscillation was made and discussed.

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Effect of Blade Angle on Aerodynamic Performance of Archimedes Spiral Wind Turbine

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences ◽

10.37934/arfmts.78.1.122136 ◽

2020 ◽

Vol 78 (1) ◽

pp. 122-136

Author(s):

Andrew Maher Labib ◽

Ahmed Farouk Abdel Gawad ◽

Mofreh Melad Nasseif

Keyword(s):

Experimental Study ◽

Wind Turbine ◽

Computational Study ◽

Computational Simulation ◽

Turbine Blades ◽

Aerodynamic Performance ◽

Small Scale ◽

Rotational Axis ◽

Blade Angle ◽

Archimedes Spiral

Energy harvesting from wind in urban areas is an important solution to meet energy needs and environmental care. This study describes the effect of blade angle on the aerodynamic performance of small-scale Archimedes spiral-wind-turbine blades by computational simulation, which is experimentally validated. Archimedes wind turbine is classified as one of the HAWTs. The computational approach was used to predict the aerodynamic performance of the scaled-down rotor blades. Blade angle is defined by the angle between the rotational axis and the tip of the blade, which varied from 50° to 65° with an interval of 5°. The computational study was carried out using the ANSYS CFX 19 software for a steady incompressible flow. The performance parameters of the wind turbine, which are power and torque coefficients were explored for different blade angles. This was carried out for wind speed from 5 to 12 m/s with an interval of 1 m/s. In order to validate the results of the computational simulation, an experimental study was carried out using a scaled-down 3D-printed models. The experimental study concentrated on the effect of blade angle on the rotating speed for the different turbine models. Obviously, the results highlight that the maximum power coefficient has an inverse relation to the blade angle.

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