EXPERIENCE OF CREATION AND RESEARCHING RESULTS OF THERMAL SOUND AUTOGENERATION BASED ON THE RIJKE TUBE
The purpose of work is creation of a working sample of Rijke pipe and research on his basis of thermal autogeneration of sound waves. In article historical aspects, the basic stages of opening and studying of different displays of the unusual physical phenomenon which are taking place on a joint of thermodynamics and acoustics are considered, the urgency of the further researches is marked, features of display and possible practical use thermo-acoustical generation are discussed. Theoretical aspects of occurrence and existence of acoustic fluctuations in the open vertically located pipe are considered. It is shown, that the column of air in a pipe can make one or own several fluctuations representing standing waves, the pipes limited to the ends on which length the integer of half waves is stacked. As the reason of excitation of fluctuations any external sound or movement of air can serve in a pipe, the greatest amplitude basic own fluctuation possesses. On the ends of a pipe units of increments of pressure of a standing sound wave, antinode oscillatory displacement and speed of particles of air are located. Not fading fluctuations are caused by continuous inflow of energy from a heater located inside the bottom part of a pipe. The role of a heater is not reduced only to creation of draft, - progress of air upwards on a pipe. Due to a heater inside Rijke pipe there is a positive acoustic feedback. The structure of self-oscillatory system includes an energy heater, oscillatory system (a column of air in a pipe), specifying frequency of fluctuations and the part of a positive feedback providing periodic during the necessary moments of time receipt of energy from a heater in oscillatory system for indemnification of losses of energy of fluctuations because of friction, radiation, etc. Known theoretical models are checked experimentally up. Dependences of the thermal capacity resulting in generation of a sound, on an arrangement of a heater and frequency of a sound on length of a pipe are investigated. Influence of a lateral aperture on failure of generation is experimentally investigated. The received results are of interest for understanding of features of occurrence and practical use of Rijke effect.