scholarly journals Influence of Quiet Spike on Supersonic Transport for Low Boom Effect

2019 ◽  
Vol 37 (1) ◽  
pp. 203-210
Author(s):  
Zhanke Li ◽  
Yang Liu ◽  
Yulin Ding ◽  
Zhijin Lei ◽  
Boping Ma
Keyword(s):  
Reference Value ◽  
Parameter Method ◽  
Present Scheme ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Multi Stage ◽  
Reduction Effect ◽  
Aerospace Corporation ◽  
Reynolds Average ◽  
Main Factor

One of the biggest technical challenges of supersonic flight is the mitigation of sonic boom. To deal with this problem, the Gulfstream Aerospace Corporation came up with the spike concept, and it showed to be efficient. However, there also remain several problems, the first one is that installing the spike makes it harder to balance for supersonic transport and the another one is that the movement equipment is complex. In this paper, a new concept by replacing the multi-stage of the normal spike with smooth transistion cones is proposed. The concept simultaneously uses the CFD solver HUNS3D based on the Reynolds average (RANS) equation and the far-field FL-BOOM sound explosion propagation program based on Thomas waveform parameter method. The effectiveness of the present scheme to suppress supersonic aircraft sound explosion is verified according to the concept. It is proved that the increased length is good for low blast and the main factor affecting the blast reduction effect of multistage mute cone is length rather than series by the analysis. The results have important reference value for the silent cone design of supersonic aircraft.

Meteorological Parameters Affecting Supersonic Transport Operations

1967 ◽  
Vol 20 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Richard Scherhag ◽  
Gunter Warnecke ◽  
Werner Wehry
Keyword(s):  
Working Group ◽  
Meteorological Parameters ◽  
Sonic Boom ◽  
Atmospheric Ozone ◽  
Atmospheric Conditions ◽  
Atmospheric Parameters ◽  
Free Atmosphere ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Initial Task

In 1965, following the Eastbourne Conference, the British, French and German Institutes of Navigation formed a Working Group to make a study of the environment in which the supersonic transport will operate and of its implications for the navigation of such aircraft. The Group's initial task has been one of education, largely through discussion of a series of papers submitted to it. Some of the papers considered have already been published in the Journal (Vol. 19) and a further selection is published below. Table I was contributed by Mr. G. E. Beck. The illustrations to these papers have not all been reproduced.1. Atmospheric Conditions. It will be useful to distinguish between different kinds of atmospheric influences on supersonic aircraft operations. They may be classed as follows:(a) Sporadic effects near the ground(b) Sporadic effects in the free atmosphere(c) Effects on sonic boom(d) Effects of atmospheric ozone(e) Permanently effective atmospheric parameters, such as temperature, density and wind.

NASA’s HSCT — Past and Future Prospects

2000 ◽  
Author(s):  
Robert A. Mercure
Keyword(s):  
Travel Time ◽  
High Speed ◽  
Far East ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Advanced Technologies ◽  
The Far East ◽  
Market Impacts ◽  
Speed Range ◽  
The Government

With the termination of the government/industry partnership on the High Speed Civil Transport (HSCT) program in late 1998, the prospects for a U.S. SuperSonic Transport (SST) appears uncertain. However, NASA’s goal of “Reducing travel time to the Far East and Europe by 50% within 25 years” remains intact. The decision by industry to build an HSCT has been postponed and there is now more time to explore advanced technologies and revolutionary concepts that could make a supersonic aircraft an environmentally compatible and economically viable success. Studies will likely continue to examine future constraints regarding flight speed, range, size, market impacts and economics. The technology challenges may appear formidable, but the potential revenue generated and the benefits realized in reduced travel time by an HSCT will provide the incentive to continue the research.

Application of Damper in the Seismic Engineering

2013 ◽  
Vol 391 ◽  
pp. 301-304
Author(s):  
Teng Fei Zhong ◽  
Yu Bai ◽  
Ya Juan Sun
Keyword(s):  
Energy Dissipation ◽  
Time History ◽  
Reference Value ◽  
Seismic Effect ◽  
Parameter Method ◽  
Stiffness Parameter ◽  
Seismic Engineering ◽  
History Of ◽  
Nonlinear Time History ◽  
Simplified Modeling

The article describes the theory and application of energy dissipation technology. Puts forward the simplified modeling and optimization of damper stiffness parameter method .Through nonlinear time history of the structure show its obvious seismic effect. Prove that the method has certain reference value of the energy dissipation design.

Dynamic Modeling of Multi-Stage Planetary Gears Coupled with Bearings in Housing

2011 ◽  
Vol 86 ◽  
pp. 30-34
Author(s):  
Zheng Ming Xiao ◽  
Da Tong Qin
Keyword(s):  
Planetary Gear ◽  
Degree Of Freedom ◽  
Design Parameters ◽  
Parameter Method ◽  
Rotational Degree ◽  
Planetary Gears ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Shield Tunnelling ◽  
Gyroscopic Effects

This work develops an analytical model of multi-stages planetary gear transmission (PGT) coupled with bearings in housing based on analyzing the displacement relationships of gearing system. The model adopts three planar degree-of-freedom for each of the central components, and the rotational degree-of-freedom for the planets of each stage. Considering the gyroscopic effects, the modified transverse-torsional model is established in the rotating Cartesian coordinates by lumped-parameter method, which is more accurate and may match with the physical model better than the purely torsional model. According to the design parameters of the 3-stage planetary gears of main reducer of shield tunnelling machine, the natural frequencies and vibration modes are investigated by using this transverse-torsional model.

A New Propulsion System Proposal for Civil Supersonic Transport: The Retractable Fan Concept

1998 ◽  
Author(s):  
Jon I. Huete ◽  
R. Singh
Keyword(s):  
Power Plant ◽  
High Power ◽  
Propulsion System ◽  
Pollutant Emissions ◽  
Double Pass ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Economic Operation ◽  
High Power Output ◽  
Subsonic Regime

The next civil supersonic aircraft project will pose a number of challenges. The propulsion system for this aircraft will have to achieve economic operation for both supersonic and subsonic regime while meeting the intended noise and pollutant emissions regulation. Whilst there are a number of proposed engines for the next generation civil supersonic aircraft, they all exhibit difficulties inherent in the engine duty. The present paper offers a simple solution based on retractable fans. The key for the success of the concept is the single stage double pass tip turbine that drives the fan. Characteristics of this unique turbine such as extra-high power output at reasonable efficiencies and low metal temperatures along with some performance aspects of the power plant are discussed. Although further investigation is still required, the performance of the system merits consideration. The work was undertaken by one of the authors as part of his MSc research project.

Some Economic and Operational Questions

1961 ◽  
Vol 65 (602) ◽  
pp. 101-104
Author(s):  
C. H. Jackson
Keyword(s):  
Well Being ◽  
Social Implications ◽  
Technical Challenge ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
The Times ◽  
Do So

The argument for the supersonic transport seems to run as follows: it offers a new and faster way to go places; it might not cost more to do so; it ought to create new wealth, and its influence on human affairs, although not clearly foreseeable, surely will be beneficial. There is a certain amount of evidence to warrant optimism; there are issues of national prestige and well-being; the technical challenge is exciting; so “ Let us somehow find finance and proceed.”Operators agree that the design and operational problems of supersonic aircraft, one of the possible great advances in transport, are complex and interesting; they might also speculate on its likely social implications, though this is an unrewarding pastime. The operators accept that the aircraft probably will be developed, for it is as much a challenge of the times as have been all the great innovations of routes and vehicles from Columbus right through to our day; but as has always been the case, before any commitment, they must seek assurance of ultimate economic soundness.

Supersonic Aircraft—Promise and Problems

1960 ◽  
Vol 64 (594) ◽  
pp. 315-334 ◽  
Author(s):  
M. B. Morgan
Keyword(s):  
The United States ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Stability And Control ◽  
The Subject ◽  
Scientific Adviser ◽  
Mach 3 ◽  
Short Time ◽  
And Control ◽  
Made In

The 1,157th lecture to be given before the Society, “Supersonic Aircraft—Promise and Problems” by M. B. Morgan, Esq., C.B., M.A., F.R.Ae.S., Scientific Adviser to the Air Ministry, was given on 17th March 1960, at the Institution of Mechanical Engineers. Mr. Peter G. Masefield, M.A., F.R.Ae.S., Hon.F.l.A.S., M.Inst.T., President of the Society, presided. Opening the meeting Mr. Masefield said he thought this would be one of the most interesting and stimulating lectures of the session. The subject of the supersonic aeroplane had been freely discussed in the United States and probably in Russia also. In this country they had been more reticent so he hoped they would have a really good discussion after this lecture. One significant point was that people no longer wondered whether a supersonic transport could, or should, be built but only whether it should cruise at a Mach number of 2 and be made in light alloy, or whether it should be around Mach 3 and be made of steel or more exotic materials. That sooner or later—and many believed sooner—transports would fly at supersonic speeds at 70,000 ft. was taken for granted.Mr. Morgan was well known to them all. Born in Wales, he was educated at Rutlish, Merton and St. Catharine's College, Cambridge, where he took the Mechanical Sciences Tripos and won the John Bernard Seely Prize in Aeronautics in 1934. In fact, he and Mr. Morgan used to enjoy the Cam together and Mr. Morgan looked little different today than he had in those days. Mr. Morgan was apprenticed to Mather and Piatt Ltd. and also spent a short time at Vickers, Weybridge before joining the R.A.E., Farnborough in 1935. Since then he had specialised in aerodynamics, flight research and development, stability and control and, he had taken his Pilot's Licence in 1944. He was Head of the Aero Flight Section of the R.A.E. from 1946-1948, Head of the Guided Weapons Department from 1948-1953 and Deputy Director of the Establishment from 1954 until 1959. He had then been appointed to his present position of Scientific Adviser to the Air Ministry and had also been Chairman of what had come to be known as “STAC”–Supersonic Transport Aircraft Committee. He felt that they could have no better person than Mr. Morgan to talk on the Supersonic Transport.

Dynamic Characteristics of Planetary Gearbox of Shield Tunnelling Machine

2010 ◽  
Vol 139-141 ◽  
pp. 2413-2417
Author(s):  
Zheng Ming Xiao ◽  
Da Tong Qin
Keyword(s):  
High Efficiency ◽  
Critical Issue ◽  
Design Parameters ◽  
Parameter Method ◽  
Subway Tunnel ◽  
Fe Method ◽  
Shield Tunneling ◽  
Planetary Gears ◽  
Planetary Gearbox ◽  
Multi Stage

Shield tunneling machine(STM) is a safety and high-efficiency excavator in the subway tunnel project, but the dynamics of whose multi-stage planetary gearbox is still a critical issue. In this paper, the torsional dynamic model for three-stage planetary gears train(PGT) is developed by lumped parameter method. According to the configuration and design parameters of the planetary gearbox, the natural frequencies are calculated, and the vibration modes are also analyzed. The natural modes can be classified into one of the three categories: rigid-body mode, distinct modes and planet modes. By using finite element(FE) method, the vibration characteristics of gearbox housing are also computed and analyzed for lucubrating vibration transfer and coupling between planetary gears train and housing, which is the important foundation for dynamic optimization of planetary gearbox.

Diagnosis of Carpal Tunnel Syndrome: The Role of RANTES

2021 ◽  
Vol 19 (4) ◽  
pp. 65-70
Author(s):  
Ihsan M. Ajeena ◽  
Rihab H. Al-Mudhafar ◽  
Iman J. Al-Awadi ◽  
Hasanain A. Al-Khalidi ◽  
Nawrass J. Alsalihi
Keyword(s):  
Carpal Tunnel Syndrome ◽  
Carpal Tunnel ◽  
Reference Value ◽  
Signs And Symptoms ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
High Prevalence ◽  
Tunnel Syndrome ◽  
Main Factor

Carpal tunnel syndrome (CTS) is regarded as most frequent entrapment neuropathy in upper extremities with high prevalence in females. It is a multi-factorial disease that had signs and symptoms due to compression of median nerve at the carpal tunnel in wrist, although may be asymptomatic. Immune system has been recognized as the main factor of neuropathic pain. Regulated on Activation, Normal T cell Expressed and Secreted (RANTES) is among the cytokines that revealed a dysregulated pattern of neuropathy specific cytokine profile in CTS and, in human, it is encoded by CCL5 gene. Sixty-four patients suffering from CTS were enrolled in this controlled cross sectional study. For all, nerve conduction study was performed to prove the diagnosis of CTS and to classify its severity. The mean age of all patients was 44.9±7.8 years, 89.1 % were female, 40.7% had mild type CTS and 40.7 % had right side CTS. 5 ml blood was obtained from each participant to measure the level of serum RANTES using specific ELISA kit. There was significant high RANTES levels in CTS patients when compared with its reference value. We conclude that RANTES level increases in patients with carpal tunnel syndrome and can be used as a predictor for its diagnosis despite its proposed neuroprotective role.

The Minimum Navigational Equipment for Supersonic Transport

1964 ◽  
Vol 17 (4) ◽  
pp. 426-433
Author(s):  
J. Hardouin
Keyword(s):  
Traffic Control ◽  
Air Traffic Control ◽  
Air Traffic ◽  
Reasonable Time ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Aircraft Navigation

The navigational problems presented by supersonic aircraft do not differ essentially from those with modern four-jet aircraft. Navigation will still entail three main tasks:i. To ensure that the crew knows the position of the aircraft at any given moment, within a reasonable time, and with the necessary accuracy.ii. To ensure that the aircraft is operated under the best conditions of route, speed and height for profitable operation.iii. To ensure compliance with air traffic control.

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