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The purpose of this paper is to find the optimum design of diffuser of supersonic wind tunnel in order to access the minimum overall pressure drop in wind tunnel, using evolutionary algorithm.

The authors developed a genetic algorithm (GA) code to calculate the shape of a diffuser with flexible walls in order to have the maximum pressure recovery. The two-dimensional turbulent and compressible flow was analyzed numerically using shear-stress transport and Advection Upstream Splitting Method (AUSM)+ turbulence models and its optimization with GA.

The results of this study indicate that elitist GA promises a powerful method for optimization of the wind tunnel diffuser. Separation zone is reduced by 22.2 percent at the convergent part of diffuser and 56 percent at the divergent part of diffuser. The efficiency of new optimized wind tunnel diffuser increased by 83 percent in comparison to the sample of supersonic wind tunnel.

It has been observed that AUSM+ method and shape design optimization using GA are robust and efficient technique to optimize wind tunnel diffuser.

ON Friday, March 24, 1961, the Minister of Aviation, Mr Peter Thorneyeroft, officially opened a new high supersonic speed wind tunnel at the Royal Aircraft Establishment, Bedford. This tunnel provides the final stage in the present plans for expansion of the wind tunnel facilities at Bedford, being capable of providing speeds from Mach 2.5 up to Mach 5 in a working section measuring 4x3 ft. Three other tunnels arc already in operation at Bedford—these being the 13x9 ft. working section low‐speed tunnel, the 3x3 ft. tunnel, which is transonic and supersonic to Mach 2, and the 8x8 ft. tunnel, which is subsonic and supersonic to Mach 2.8.

THE large transonic wind tunnel of the Aircraft Research Association Ltd, at Bedford was described in an article in the May 1956 issue of AIRCRAFT ENGINEERING. The 2 ft. 6 in. × 2 ft. 3 in. supersonic tunnel which was at that time planned is now complete and running. This tunnel is driven by the 13,750 h.p. axial compressor which also serves to evacuate the ventilated working section of the transonic tunnel. This compressor can be isolated from the transonic tunnel, which can then still be operated in the subsonic range, by motorized valves, the operation taking only a few minutes.

ON October 19 the Minister of Aviation formally opened the two new high‐speed wind tunnels which have been constructed at Wharton, Lancashire, for English Electric Aviation Ltd.

This paper aims to propose a dedicated measurement methodology able to simultaneously determine the stability derivative C_mα̇ and the pitch damping coefficient sum C_mq + C_mα̇ in a wind tunnel using a single and almost non-intrusive metrological setup called MiRo.

To assess the MiRo method’s reliability, repeatability and accuracy, the measurements obtained with this technique are compared to other sources like aerodynamic balance measurements, alternative wind tunnel measurements, Ludwieg tube measurements, free-flight measurements and computational fluid dynamics (CFD) simulations. Two different numerical approaches are compared and used to validate the MiRo method. The first numerical method forces the projectile to describe a pure oscillation motion with small amplitude along the pitch axis during a rectilinear flight, whereas the second numerical approach couples the one degrees of freedom simulation motion equations with CFD methods.

MiRo, a novel and almost non-intrusive technique for dynamic wind tunnel measurements, has been validated by comparison with five other experimental and numerical methodologies. Despite two completely different approaches, both numerical methods give almost identical results and show that the holding system has nearly no impact on the dynamic aerodynamic coefficients. Therefore, it could be assessed that the attitude of MiRo model in the wind tunnel is very close to the free-flight one.

The MiRo method allows studying the attitude of a projectile in a wind tunnel with the least possible impact on the flow around a model.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

A Summary by Dr. Alexander Klemin of the Papers Presented Before the Fourteenth Meeting of the Institute held at Columbia University, New York, on January 29–31, 1946. AERODYNAMICS IN spite of increased wing loadings, the use of full span wing flaps has been delayed, because of inability to find a suitable aileron. The Development of a Lateral‐Control System for use with Large‐Span Flaps by I. L. Ashkenas (Northrop Aircraft), outlines the various steps in the aerodynamic development of a retractable aileron system well adapted to the full span flap and successfully employed on the Northrop P‐61. Included is a discussion of the basic data used, the design calculations made, and the effect of structural and mechanical considerations. Changes made as a result of preliminary flight tests are discussed and the final flight‐test results are presented. It is concluded that the use of this retractable aileron system has, in addition to the basic advantage of increased flap span, the following desirable control characteristics: (a) favourable yawing moments, (b) low wing‐torsional loads, (c) small pilot forces, even at high speed.

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.

In this article, the author gives a detailed description of the Laboratory which possesses a wind‐tunnel for normal aerodynamic research and another for particularly high speeds—the supersonic wind‐tunnel. The normal tunnel has several points of interest; it can be used cither open or closed and, in the latter case, it is possible to achieve a particularly good pressure distribution. The controls and measuring devices are described.

THE development of undergraduate teaching in Aeronautical Engineering at Manchester University has followed a different pattern from that in most other Universities in this country. Although Osborne Reynolds carried out his famous experiments in the Engineering Department at Manchester, the teaching of Aeronautical Engineering grew out of Mathematics rather than out of Engineering. For a large proportion of the past 80 years the Chair of Applied Mathematics has been held by men eminent in the field of Fluid Mechanics: Lamb, Goldstein and Lighthill must surely be names well‐known to every aeronautical engineer. It was due to the initiative of Professor S. Goldstein that a separate Department of Fluid Mechanics was set up in 1946 under the direction of Mr W. A. Mair. At first it was natural that the emphasis should be on experimental work to complement the theoretical work carried out in the Mathematics Department. Later, however, although close relations with the Mathematics Department were still maintained, the Mechanics of Fluids Department developed into a separate entity making both theoretical and experimental contributions to fundamental knowledge.