scholarly journals Effect of airfoil thickness on cargo carrying capacity for high speed ship with aerodynamic unloading

Author(s):  
М.С. Каунг

В последние несколько лет, высокоскоростные суда с аэродинамической разгрузкой вызывают интерес, как в гражданском, так и военно-морском транспорте. Было проведено много исследований аэродинамических профилей около границы раздела. Но исследований грузоподъемности крыла для этого типа судов было мало. В данной работе численно оценивалось влияние толщины профиля на грузоподъемность высокоскоростного суда с аэродинамической разгрузкой. Для изучения влияния толщины аэродинамического профиля в диапазоне от 10% до 60% хорды, были проведены расчеты на движущемся экране при углах атаки от 0° до 8° и (h/c = 0,1). Все аэродинамические профили имели хорду 1 м. Профили были модифицированы и имели плоскую нижнюю поверхность, чтобы избежать присасывания на малых углах атаки при малом отстоянии от границы раздела. Поскольку это является нежелательным явлением. Модель турбулентности k-ω SST использовалась для моделирования обтекания крыла при числах Рейнольдса (R_e = 〖1×10〗^6). Для проверки результатов расчетов результаты CFD профиля NACA 4412 при движении над землей были сопоставлены с экспериментальными данными. В данной статье показано, какой тип толщины крылового профиля следует использовать для получения эффективной грузоподъемности высокоскоростного суда с аэродинамической разгрузкой при его проектировании. In the past few years, high-speed aerodynamic unloading vessels have attracted interest in both civilian and naval transport. There have been many studies of airfoils near the interface. But there has been little research on wing loading for this type of vessel. In this study, the effect of the profile thickness on the carrying capacity of a high-speed vehicle with aerodynamic unloading was numerically estimated. To study the effect of the thickness of the airfoil in the range from 10% to 60% of the chord, calculations were carried out on a moving screen at angles of attack from 0 ° to 8 ° and (h / c = 0.1). All airfoils had a chord of 1 m. The airfoils were modified to have a flat bottom surface to avoid suction at low angles of attack with a small distance from the interface. As this is an undesirable phenomenon. The k-ω SST turbulence model was used to simulate the flow around the wing at Reynolds numbers (R_e = 〖1×10〗^6). To check the calculation results, the CFD results of the NACA 4412 profile when moving above the ground were compared with the experimental data. This article shows what type of airfoil thickness should be used to obtain the effective carrying capacity of a high-speed aerodynamic craft in its design.

Author(s):  
William Krakow

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.


Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions


Author(s):  
Peter H. Wiebe ◽  
Ann Bucklin ◽  
Mark Benfield

This chapter reviews traditional and new zooplankton sampling techniques, sample preservation, and sample analysis, and provides the sources where in-depth discussion of these topics is addressed. The net systems that have been developed over the past 100+ years, many of which are still in use today, can be categorized into eight groups: non-opening/closing nets, simple opening/closing nets, high-speed samplers, neuston samplers, planktobenthos plankton nets, closing cod-end samplers, multiple net systems, and moored plankton collection systems. Methods of sample preservation include preservation for sample enumeration and taxonomic morphological analysis, and preservation of samples for genetic analysis. Methods of analysis of zooplankton samples include determination of biomass, taxonomic composition, and size by traditional methods; and genetic analysis of zooplankton samples.


Queue ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 77-93
Author(s):  
Niklas Blum ◽  
Serge Lachapelle ◽  
Harald Alvestrand

In this time of pandemic, the world has turned to Internet-based, RTC (realtime communication) as never before. The number of RTC products has, over the past decade, exploded in large part because of cheaper high-speed network access and more powerful devices, but also because of an open, royalty-free platform called WebRTC. WebRTC is growing from enabling useful experiences to being essential in allowing billions to continue their work and education, and keep vital human contact during a pandemic. The opportunities and impact that lie ahead for WebRTC are intriguing indeed.


2012 ◽  
Vol 487 ◽  
pp. 203-207
Author(s):  
Gong Xue Zhang ◽  
Xiao Kai Shen

Purpose, with the application of workbench finite element analysis software, get the analysis results of DVG 850 high-speed vertical machining center via the modal analysis and harmonic response analysis. Use the calculation results for reference, put forward the improved method, and prove the credibility of the simulation analysis by testing DVG 850 prototype.


This is the first occasion on which I have had the great honour of addressing the Royal Society on this anniversary of its foundation. According to custom, I begin with brief mention of those whom death has taken from our Fellowship during the past year, and whose memories we honour. Alfred Young (1873-1940), distinguished for his contributions to pure mathematics, was half brother to another of our Fellows, Sydney Young, a chemist of eminence. Alfred Young had an insight into the symbolic structure and manipulation of algebra, which gave him a special place among his mathematical contemporaries. After a successful career at Cambridge he entered the Church, and passed his later years in the country rectory of Birdbrook, Essex. His devotion to mathematics continued, however, throughout his life, and he published a steady stream of work in the branch of algebra which he had invented, and named ‘quantitative substitutional analysis’. He lived to see his methods adopted by Weyl in his quantum mechanics and spectroscopy. He was elected to our Fellowship in 1934. With the death of Miles Walker (1868-1941) the Society loses a pioneer in large-scale electrical engineering. Walker was a man of wide interests. He was trained first for the law, and even followed its practice for a period. Later he studied electrical engineering under Sylvanus Thompson at the Finsbury Technical College and became his assistant for several years. Thereafter, encouraged by Thompson, he entered St John’s College, Cambridge, with a scholarship, and graduated with 1st Class Honours in both the Natural Sciences and the Engineering Tripos. Having entered the service of the British Westinghouse Company, he was sent by them to the United States of America to study electrical engineering with the parent company in Pittsburgh. On his return to England he became their leading designer of high-speed electrical generators


1974 ◽  
Vol 96 (2) ◽  
pp. 193-203 ◽  
Author(s):  
J. K. Hedrick ◽  
G. F. Billington ◽  
D. A. Dreesbach

This article applies state variable techniques to high speed vehicle suspension design. When a reasonably complex suspension model is treated, the greater adaptability of state variable techniques to digital computer application makes it more attractive than the commonly used integral transform method. A vehicle suspension model is developed, state variable techniques are applied, numerical methods are presented, and, finally, an optimization algorithm is chosen to select suspension parameters. A fairly complete bibliography is included in each of these areas. The state variable technique is illustrated in the solution of two suspension optimization problems. First, the vertical plane suspension of a high speed vehicle subject to guideway and aerodynamic inputs will be analyzed. The vehicle model, including primary and secondary suspension systems, and subject to both heave and pitch motions, has thirteen state variables. Second, the horizontal plane suspension of a high speed vehicle subject to guideway and lateral aerodynamic inputs is analyzed. This model also has thirteen state variables. The suspension parameters of both these models are optimized. Numerical results are presented for a representative vehicle, showing time response, mean square values, optimized suspension parameters, system eigenvalues, and acceleration spectral densities.


China Report ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 289-308
Author(s):  
Takeshi Daimon-Sato

For the past decade, China and Japan have been competing against each other over aid market with its implicit intention to pursue their economic interests, which turned into a rivalry between two diplomatic concepts: Chinese Belt and Road Initiative (BRI) versus Japanese Free and Open Indo-Pacific (FOIP) Strategy. The severe competition over high-speed rail (HSR) by two countries, joined by French and German competitors, has been intensified for the benefit of China, taking all of its catchup benefits with its dubious sense of rule of law. This article asks if the two initiatives can coexist with the entry of India into the game and form an equilibrium of ‘grand coalition’, benefiting all its players as ‘win-win-win’ game, which turns out to be feasible and unstable. Nevertheless, Japan still seems to have a good reason to keep India as a strategic partner of FOIP as well as a ‘gateway’ for Central and Western Asia with fragile states such as Afghanistan and Pakistan, and official development assistance (ODA) could play a significant catalyst role as ‘human security’ promoted by Professor Amartya Sen and ex-UNHCR Ms. Sadako Ogata. The COVID-19 pandemic together with the exit of the isolationist US administration may provide the world with glimmering sense of hope for the year 2021 and beyond, if and only if one becomes more aware of the complementarities of comparative advantage of China, India and Japan to pursue common interests.


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