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Abstract

It has been established that Industrial Aerodynamic wind tunnel tests should be carried out in flows which model atmospheric boundary layers. In order that the models being tested should be of an adequate size these boundary layers should be as deep as possible. Such a boundary layer can be produced naturally in a wind tunnel having a very long working section; the object of this work has been to devise a system which would reproduce flows having the structure of Adiabatic boundary layers in a few boundary layer heights.

There are some conflicting opinions in the literature as to the nature of the boundary layer structure for various terrain types or, how the flow structure varies as a function of the terrain roughness. Consequently, the first part of the work was concerned with deriving the boundary layer structure appropriate to flow over various types of terrain. This was done by reviewing and analysing the available meteorological literature for the period 1880 - 1972.

The analysed data are finally presented as a function of the roughness lengths appropriate to various types of terrains and these data are considered to be the most representative available for Adiabatic boundary layers. Many methods of simulating such flows have been attempted; these have been briefly reviewed in the second part of the work and were generally found to produce flows which did not have all of the required turbulence characteristics. The method described here produced all of the mean and turbulent flow properties required in a length of between three and four and one half boundary layer heights. In the first instance the flow appropriate to rural terrain was produced and subsequently, with the system for producing the flow partly modified, the flow characteristics of urban terrain were simulated. The structure of both of these boundary layers was consistent with that predicted by the analysed atmospheric data.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology T Technology > TA Engineering (General). Civil engineering (General) T Technology > TL Motor vehicles. Aeronautics. Astronautics
Departments:	School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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