No abstract

Представлены результаты экспериментального исследования влияния параметров импульсного разряда на возбуждаемые им локализованные пульсации в сверхзвуковом пограничном слое плоской пластины. Эксперименты выполнены в сверхзвуковой малотурбулентной аэродинамической трубе Т-325 ИТПМ СО РАН при числе Маха М = 2. Экспериментально установлено, что длительность разряда влияет на пространственные масштабы и амплитуду генерируемых возмущений. Исследована эволюция вниз по потоку локализованных возмущений различной амплитуды. Оценена скорость распространения контролируемых пульсаций в пограничном слое. Обнаружены линейный и нелинейный режимы развития локализованных возмущений. Ключевые слова: сверхзвуковой поток, импульсный разряд, контролируемый эксперимент, пограничный слой, термоанемометрия.

A method of exciting of artificial disturbances localized in space and time (wave packets) in a supersonic boundary layer is developed. Experimental investigations are carried out in the low noise supersonic wind tunnel T-325 at Mach M = 2. A model of a flat steel plate with a sharp leading edge is used. Measurements of mean flow and fluctuations are performed by using a constant temperature anemometer. To generate controlled fluctuations the short time surface glow discharge is used. Measurements of controlled disturbances are synchronized in time with glow discharge ignition. To increase the signal-to-noise ratio the time trace averaging technique is applied. Electrical power and polarity of the glow discharge initiation are changed to see their influence on the initial wave packet amplitude. Optimal glow discharge parameters for generation of artificial disturbances are found. The experimental data on the localized disturbances evolution in boundary layer are received. It is obtained that the velocity of the wave packet propagation has speed close to the free stream for the leading wave edge. The trailing edge of the wave packet spreads with subsonic speed relatively the supersonic flow. The wave packet propagates in both the streamwise and spanwise directions. Half-angle of this spreading is approximately equal to 10 degrees relative to the free stream direction. It has been found, that the wave packet is developed inside the boundary layer near of the artificial pulsations source. However the evolution of controlled disturbances leads to their radiation into free flow

Experimental study of the influence of flow pulsation in settling chamber on the supersonic free stream disturbances was carried out. Data on the pulsations in the settling chamber and the efficiency of deturbulization system as well as the correlation of pulsations of the flow of settling chamber and flow pulsations in test section of T-325 supersonic wind tunnel of ITAM SB RAS were obtained.