Studies on Biplane Wind Vanes, Ventilator Tubes and Cup Anemometers ( I )

Abstract

In Part I, mathematical treatment of the problems, is presented to establish the theoretical support and leading principles of the experiments and actua techniques.In Part II, experimental. results based upon the mathematical principles are described for various actually designed instruments.In Chapter 1, Part I, rigorous discussions are given for the force and moment experienced by two flat plates with arbitary chord lengths, angle of stagger and decalage in two-dimensinal incompressible ideal fluid, The problem is solved after the method of I. E. Garrick but more general result due to J. Hodgkinson and E. G. C. Poole is analysed and the connection is found between them, Formulae for the cases of two plates in close proximity are given. Numerical calulations are carried out for symmetrical biplane wind vanes and fundamental principles are found for design use.In Chapter 2, Part I, exact formulae are induced for the calculation of the flux through the ventilator tubes with straight, circular, elliptic or hyperbolic sides in two-dimension. Numerical evaluations are done for the cases of straight and hyperbolic sides.In Chapter 3, Part I, basic considerations of cup anemometers are effected, and numerical calculation of the static moment of cylindrical windmill with two rotors is made for an example,In Chapter 1, Part If, three types of combined wind vane and anemometer with twin-rudder, conical tail ring, or hollow single rudder each of which may be regarded as posessing biplane characteristics, are tested in the wind tunnel. After systematic investigation based upon the theoretical oint of view one type of them is decided to be favourable for directional stability. Also anemometer windmill blades are discussed, which are indifferent to the effect of wind turbulence,In Chapter 2, Part II, systematic studies on the basic forms of straight ventilator tubes are done. Two effective. groups are found. The test was also carried out for tubes with free-running windmill. The trends of the experiments agree with theory. Numerous actual designs with, bent air passage are tested for radiosonde use. The theoretical leadership still holds in such complicated examples.Cowled windmill models are tested of their torqud and power and compared with those of windmill alan. e. The effect of the cowling is not highly promissing but several important fundamental characteristics of windmill are revealed. Free-running windmill or windmill anemometer is also treated. A full-scale windmill is experimented in natural wind.Two types of cowled hot-wire anemometer are investigated of their directional insensitiveness to the wind.In Chapter 3, Part II, cylindrical windmill' model with two rotors is tested of its troque and power, and also discussed as an anemometer.