To ensure meaningful evaluation and prediction of configuration and flight effects on aircraft noise generation and propagation, reliable representation and measurement of relevant aerodynamic flow conditions as well as of acoustic characteristics must be possible. Acoustic wind tunnels, with models mounted in a quiet test section airstream surrounded by an anechoic working chamber, have now been established as primary tools for noise-model research work and should next be exploited also for the direct support of specific quiet aircraft projects. The special advantages of such tunnels in ensuring a more sheltered and controlled environment than outdoor mobile-model facilities and flight testing include capability of continuous operation, repeatable test conditions, high productivity, good measurement accuracy, testing flexibility, and the precise alleviation of reflections from neighbouring surfaces. Of course the recent experience on noise testing under forward speed conditions and on associated techniques is still very limited at both model scale and full scale, as compared with extensive and continuous aerodynamic testing over half a century. However, many of the problem areas associated with subsonic tunnel design and application for noise-model testing, as identified over five years ago, have now been clarified. Also, the special treatments or limitations involved have become quantifiable in many respects, as discussed later under the convenient main headings of tunnel test section requirements (section 2), tunnel circuit design (section 3), special measurement and analysis techniques (section 4) and model scale simulation (section 5).

The Light Aeroplane Group of the Royal Aeronautical Society was set up with the aim of encouraging activity in the light aeroplane field in Britain and its hope is that production of light aircraft should be restarted in this country. Clearly there are many problems to be faced in setting about the renaissance of an industry which will range far beyond the scope of those encountered in building a ‘one-off’ aeroplane. In this paper I shall present three case studies of light aircraft produced in the recent generation. I hope that this will give a reasonably complete picture of the implications of starting light aeroplane production and will therefore form a good basis for discussion.

In formulating the design competition which has just been announced, we have taken note of the market appraisal which Hugh Field presented at Cranfield in September 1977 in which he pointed out that there is still a lack of a really good training aeroplane in the world market and also of the specification that Alan Bramson has put forward for the so called Multi Role Club Aeroplane which is aimed at just that slot in the market. The results from Alan Bramson's survey of opinion from flying instructors showed the acceptability of a low-wing, tricycle undercarriage monoplane with side-by-side seating.

Future developments and trends in the data processing industry will have an earlier and stronger impact on aerospace than upon any other segment of industry. The use of data processing by aerospace in scientific, administrative and automation applications typically precedes and anticipates that of society and industry at large. My discussion, therefore, will focus on the total use of data processing and its technologies in our industrial-based societies. First, I will present an overview of data processing in terms of usage and dollars, then look at the world of computers a decade hence from a user's and administrator's point of view. Then I will offer a view of that world of computers from a technologist's point of view, and finally, discuss the impact of such a scenario on our society.

The term data processing industry, as I will use it, includes all those who are involved in providing data processing capabilities: equipment and software manufacturers, programming and operations staffs of user installations, professional data processing organisations, and university and research computer science groups. In short, those who design and produce our computer-based systems and services.

Axial, normal (radial) and tangential turbulence intensity measurements have been carried out in the past in pipe and two-dimensional channel flows, e.g. Refs. 1-9. A similarity in the distribution of these turbulence intensities is observed. They are all minimum at the centreline, increasing steadily as the wall is approached, until they reach some maximum values close to the wall, then they start to decrease as the wall is approached further. Furthermore, the three components of turbulence intensity have been observed to vary in a similar way with the Reynolds number.

On the other hand, the Prandtl mixing length theory assumes that the turbulent fluctuations are proportional to the product of a local mixing length and a velocity gradient. This implies that the turbulence fluctuations are directly proportional to each other. It is, therefore, found worthwhile examining the possibility of a relationship between the turbulence intensities. Smooth pipe and channel flows are chosen for this purpose.