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The dynamics of a transitional propane jet diffusion flame with a fuel‐jet velocity of 2.2 m/s has been studied using an implicit, third‐order‐accurate, upwind numerical scheme. The large‐scale vortices outside the flame surface and the small‐scale ones inside were simulated simultaneously, and their interactions with the flame surface were investigated. Numerical experiments were conducted to gain insight into the influence of buoyancy and shear‐layer forcing on the development of the outer and inner vortices. In the presence of buoyancy forces, the outer vortices developed as part of the solution, and the vortex‐crossing frequency was approximately 15 Hz. The inner structures were manifested from a weak perturbation the vorticity that was introduced at the nozzle exit, and, at 185 Hz, these vortices were found to travel farther downstream. It was also found that the inner vortices do not play a role in the formation of the outer vortices, and vice versa. However, the growth of the inner vortices in the downstream locations is strongly influenced by the slowly moving outer vortices.

The goal of this review paper is to provide information on several commonly used thermography techniques in semiconductor and micro‐device industry and research today.

The temperature imaging or mapping techniques include thin coating methods such as liquid crystal thermography and fluorescence microthermography, contact mechanical methods such as scanning thermal microscopy, and optical techniques such as infrared microscopy and thermoreflectance. Their principles, characteristics and applications are discussed.

Thermal issues play an important part in optimizing the performance and reliability of high‐frequency and high‐packing density electronic circuits. To improve the performance and reliability of microelectronic devices and also to validate thermal models, accurate knowledge of local temperatures and thermal properties is required.

The paper provides readers, especially technical engineers in industry, a general knowledge of several commonly used thermography techniques in the semiconductor and micro‐device industries.

The purpose of this paper is to study the combustion and emission characteristics of an improved trapped vortex combustor (TVC).

An experiment is carried out to study the effect of the bluff bodies’ layout on the flow of the improved TVC. Results confirm that an equation achieving the proper cavity size of a TVC can be used to design the reasonable configuration of the improved TVC. A numerical simulation is used to study the flow, combustion and emission characteristics of the improved TVC.

The flow resistance, the vortex configuration, the combustion efficiency and the emissions of the improved TVC are influenced by the equivalence ratio of the main flow, the position and the flow injection angle in the cavity.

The investigation on the lean-premixed combustion of the improved TVC will provide a theory basis for the design of the improved TVC.

The improved TVC will be used in the gas turbines burning synfuels. There are the implications which offer an opportunity to avoid use of diluent gas to reduce the flame temperatures of the combustion in the gas turbines burning synfuels.

The improved TVC with the reasonable layout of the bluff bodies provides a method implementing lean-premixed combustion in the gas turbines burning synfuels.

DONCASTER'S new Central Library was formally opened on 29th December 1969 on precisely the 100th anniversary of the opening of the first public library in Doncaster. Conforming to tradition, the Library was opened by the Mayor of Doncaster, Councillor Marcus Outwin. The President of the Library Association, Mr. Wilfred Ashworth, addressed the assembled guests, his last official appointment before relinquishing the office.

The purpose of this paper is to comprehensively evaluate the progress in the development of trapped vortex combustors (TVCs) in the past three decades. The review aims to identify the needs, predict the scope and discuss the challenges of numerical simulations in TVCs applied to gas turbines.

TVC is an emerging combustion technology for achieving low emissions in gas turbine combustors. The overall operation of such TVCs can be on very lean mixture ratio and hence it helps in achieving high combustion efficiency and low overall emission levels. This review introduces the TVC concept and the evolution of this technology in the past three decades. Various geometries that were explored in TVC research are listed and their operating principles are explained. The review then categorically arranges the progress in computational studies applied to TVCs.

Analyzing extensive literature on TVCs the review discusses results of numerical simulations of various TVC geometries. Numerical simulations that were used to optimize TVC geometry and to enhance mixing are discussed. Reactive flow studies to comprehend flame stability and emission characteristics are then listed for different TVC geometries.

To the best of the authors’ knowledge, this review is the first of its kind to discuss extensively the computational progress in TVC development specific to gas turbine engines. Earlier review on TVC covers a wide variety of applications including land-based gas turbines, supersonic Ramjets, incinerators and hence compromise on the depth of analysis given to gas turbine engine applications. This review also comprehensively group the numerical studies based on geometry, flow and operating conditions.

The purpose of this paper is to establish a freestream computational fluid dynamics (CFD) model of a three-dimensional non-spinning semi-cylindrical missile model with a single wrap around fin in Mach 2.70-3.00M range and 0° angle of attack, and ultimately establishing itself for future research study.

In this study, the behaviour of flow around the fin was investigated using a κ-ϵ turbulence model of second-order of discretization. This was done using a highly structured mesh. Additionally, an inviscid CFD simulation involving the same boundary conditions have also been carried out for comparison.

The obtained values of aerodynamic coefficients and pressure contours visualizations are compared against their experimental and computational counterparts. A typical missile aerodynamic characteristic trend can be seen in the current CFD.

The predicted values of the aerodynamic coefficients of this single fin model have also been compared to those of the full missile body comprising of four fins from the previous research studies, and a similar aerodynamic trend can be seen.

This study explores the possibility of the use of turbulence modelling in a single fin model of a missile and provides a basic computational model for further understanding the flow behaviour near the fin.

The purpose of this paper is to investigate the aerodynamics characteristics (especially the side force/moment and rolling characteristics), to analyze the impacts generated by different parameters of wrap-around fins (WAFs) and to find the corresponding mechanism.

The paper has adopted three different types of WAFs for the rocket configurations and the sub-regions divided technology to investigate the lateral and rolling characteristics of WAFs, including the fins with variations in span to chord ratio, thickness, leading-edge sweep, curvature radius, fin numbers, setting angles and rotated angles. Simulations have been performed at Mach numbers from 3 to 4 through an angle-of-attack range of about 0° to 10° and at model rolling angles of 45° to 90°.

The paper shows that the WAF configurations can greatly improve the longitudinal stability and enhance the longitudinal aerodynamic characteristics for the whole rocket. The total drag of the whole rocket is mainly stemmed from the body, while the drag generated by the WAF account for only about 7.42 per cent. The extra side forces and rolling moments are due largely to the unequal pressure distributions on both sides of the fin (windward or leeward). Maintaining a certain negative setting angle (d) can effectively avoid the coning movement and improve the flight stability at high angles of attack. The size of the span and chord are two main factors in controlling the longitudinal characteristics. For the side force/moment and rolling characteristics, different geometric parameters of the WAFs have played different roles.

The paper provides the qualitative and quantitative analysis for different WAFs configurations by investigating the curves of different parameters and contouring of static pressure distributions. Findings can provide some suggestions for the designers for avoiding some significant dynamic problems, such as Magnus instability and roll rate variations during flight.

“THACKERAY HOTEL!” The order was given many times during the Easter week end by library assistants, but mainly during Thursday afternoon and evening and Good Friday morning. Members of the Easter School were arriving from various parts of the country and the Continent, and the metropolitan members were intent upon making all haste to headquarters. No one could be there too soon, and a number of provincials had been fortunate enough to get to town during the earlier part of Thursday. The Hon. Secretary was one of the first arrivals. Officially, his duty to the Association demanded his presence; unofficially, one suspected he was anticipating a good time, but he was entitled to the latter provided he fulfilled the former. Had his enjoyment depended upon the success of his arrangements he would have found it difficult to crowd it into the time the school lasted, for results showed that it would not have been possible to improve the programme or the manner in which it was carried out.

DAMAGE to libraries has assumed dimensions which make it unlikely that any private beneficence alone will be able to effect restoration. Nor is it probable that we have reached anything like the end of the destruction. Libraries are in the nature of things in great centres of population which are main targets of the enemy and they suffer accordingly. There is every hope that after the war the most determined effort will be made to repair every form of loss, and the libraries must be kept well to the fore by those who have charge of them; but the effort, in which we certainly hope such benevolent institutions as the Carnegie and similar trusts will assist, must be a universal one. It will also be considered a state obligation, we hope, based partly upon the State Insurance Scheme. In connexion with this, some librarians have had difficulty in persuading their authorities to insure books for anything like the money it would cost to replace them; it is curious that public men appear to think that books cost little or nothing! A reflection of this from the other side was the remark of a District Valuer on a claim for damage which certainly could not replace the lost books, that it was “excessive.” Cover should certainly be adequate.

The purpose of this paper is to present a novel method to design and manufacture rapid prototyping (RP) lightweight photopolymer‐resin models for wind‐tunnel tests. This method can ensure the structural configuration similarity considering model deformation under aerodynamic loads.

Photopolymer‐resin based on RP technique was used to fabricate DLR‐F4 models. Testing in a subsonic and transonic wind tunnel was carried out and the test results were compared to analyze performance predictions.

RP photopolymer‐resin wind‐tunnel models fabricated by the design methods yielded satisfactory aerodynamic performance. The methods can decrease the model's weight and prevent resonance occurrence among the models, wind‐tunnel, and support system, shorten the processing period, and lead to decrease in manufacturing period and cost.

Stiffness shortage of the thin components, such as wing tip, often leads to deformation occurrence under aerodynamic loads in transonic wind‐tunnel tests, which has significant influence on aerodynamic characteristics of the test models. Therefore, model deformation should be taken into account in the design process.

This design and manufacture method, aerodynamic and structural combination design and structural optimization, can obtain RP lightweight photopolymer‐resin wind‐tunnel models for satisfactory aerodynamic performance, which makes RP techniques more practical for manufacturing transonic wind‐tunnel test models, considering deformation induced by aerodynamic forces such as lift force. The methods also present an inexpensive way to test and evaluate preliminary aircraft designs, in both academia and industry.