video record
Media not available in the Digital Archive
Description
This was one of the first studio-based programmes to be made all on film as part of the "Ealing" evaluation experiments. Professor Hussey illustrates the wide range of model types used in... engineering, design and planning. He selects one problem - that of galloping electricity transmission lines as a thread for this programme. To solve it he invokes a conceptual model, develops a mathematical model using graphical models, and progresses to an analogue computer model which Jon Hargrave demonstrates. Finally he goes to Bristol University, Aeronautical Engineering Department use their wind tunnel model. To conclude he picks the specific case of the CEGB's Severn crossing and discusses the solution with Dr. Alan Simpson who has done research on this.
Metadata describing this Open University video programme
Module code and title: T100, The man-made world: a foundation course
Item code: T100; 18
First transmission date: 21-05-1972
Published: 1972
Rights Statement:
Restrictions on use:
Duration: 00:23:18
+ Show more...
Producer: Colin Robinson
Contributors: Jon Hargrave; Prof. M Hussey; Alan Simpson
Publisher: BBC Open University
Keyword(s): Analogue computer model; Conceptual model; Design; Ealing evaluation experiments; Engineering; Galloping electricity transmission lines; Graphical models; Mathematical model; Model types; Planning
Footage description: Reasons for the use of models are given. Several examples are given of the use of models in improving design. Shots of model ship, model fly-over, critical path diagram. Galloping of electricity transmission lines is explained, Shot of transmission lines at rest and in galloping motion. Shots of the Tacoma Narrows Bridge disaster in 1940 showing the effect of galloping. The film sequence shows the bridge oscillating and then collapsing. The problem of galloping is used as an example of the use of models to solve design problems. Shot of weight suspended at the end of a spring It is being vibrated by hand. Overhead transmission lines. Shot of diagram of a conceptual model of the weight/spring. The formula for the vibration is shown. Shot of a perspex cylinder as a model for an iced up transmission cable. It is placed in a flow of water and the aerodynamic qualities can be seen. A diagram shows why the difference in angle of flow is important in the question of galloping. Aerodynamic qualities of ice covered cableare tested at the aeronautical engineering laboratory at University of Bristol. Shots of the laboratory and apparatus. A model of ice covered cable is placed in the wind tunnel. Effects of the wind are observed. Results are plotted on a graph. A mathematical model is built up on a diagram. Newton's second law of Motion is applied. Equations are derived for the force in the spring, the aerodynamic force, and for the motion for the mass. J. Hargrave next to board on which the mathematical model is written. He places parts of a block diagram against the appropriate equation of the mathematical model. He then puts the parts together to form a complete block diagram. Electronic counterparts of the block diagram are put in its place. An analogue computer diagram results. Shot of analogue computer. Shot of oscilloscope screen showing solution of the cable motion problem. Shots of windtunnel and model of cable undergoing further testing. Motion of the cable shown in slow motion. Motion is almost perfectly vertical. Use of the model to investigate the galloping phenomenum is reviewed. Shots of Simpson and Hussey standing under electricity transmission cables - the C.E.G.B. Southern Crossing Transmission Line from England to South Wales. Simpson tells of the galloping problem encountered here due to the aerodynamic quality of the cable itself. The lay of the strands was responsible. Shot of Simpson holding a section of the cable.
Master spool number: 6LT/70382
Production number: 00521_2516
Videofinder number: 2161
Available to public: no