Interaction analysis of two streamwise supersonic vortices by visualization methods

In this paper we present an analysis and comparison of two streamwise supersonic vortices interaction with using the methods of maximum vorticity and the ?2-criterion. Mach number of incoming flow was M? = 3. A pair of vortices was generated by two coaxial straight wings with sharp leading, tip and trailing edges. Two configurations are considered: a pair of counter-rotating vortices and a pair of co-rotating vortices. In the case of counterrotating vortices the wings attack angle was 10 degrees. In the case of co-rotating vortices the attack angle of one of the wings was 10 degrees, the attack angle of other one was -10 degrees. Numerical data were obtained in the domain of 10 wing chords downstream from a wings axis by a computational model based on the URANS equations with SA turbulence model. Numerical simulations were performed on the hybrid supercomputing system K-60 at the Keldysh Institute of Applied Mathematics RAS using the developed software package ARES for 3D turbulent flows modeling on high performance computing systems. The main simulation was performed on 224 cores. The simulations were carried out on unstructured grids with hexagonal cells.

Prevention of NEO hazard: the Russian approach

Russian Academy of Sciences (RAS) is actively working to solve the problem of preventing Near-Earth Object (NEO) hazard. The article provides the goals and objectives of preventing NEO hazard, as well as ways to achieve them. The described ways of achieving the goal are applied in RAS best. The current state and prospects of the Russian contribution to the prevention of NEO hazard are considered. Statistical data on the dynamics of observation of minor planets by Russian telescopes is presented. The structure of the NEO part of hazardous situations classifier developed by Keldysh Institute of Applied Mathematics (KIAM RAS) and structure of perspective National System Security of space activities in outer space are presented, including the system’s response to event classified as dangerous. The article is accompanied by illustrations of potentially hazardous objects in the sky, made by telescopes of the International Network of Optical Telescopes (ISON), coordinated by the KIAM RAS.

Detection and cataloging of space debris’ small-sized fragment of the 20th stellar magnitude

На обсерватории Терскольского филиала ИНАСАН 24 сентября 2020 г. на комплексе телескопа Цейсс-2000 впервые был обнаружен и наблюдался в течение двух ночей фрагмент космического мусора 20-й звездной величины на геосинхронной орбите, что соответствует размерам менее 10 см. Объект был каталогизирован в динамической базе космических объектов ИПМ им. М.В. Келдыша под номером 71113. Топоцентрическое расстояние до фрагмента во время наблюдений менялось от 36862 км до 37224 км при фазовых углах от 53 ◦ до 68 ◦ , амплитуда изменения блеска объекта - от 19-й до 21-й звездной величины в интегральном свете. Приводятся параметры орбиты и диаграммы изменения блеска. On September 24, 2020, at the Terskol observatory of INASAN, a fragment of space debris’ of the 20th magnitude in geosynchronous orbit was first detected and observed for two nights using the Zeiss-2000 telescope, which corresponds to a size of less than 10 cm. The object was catalogued in the dynamic database of space objects of the Keldysh Institute of the RAS under the number 71113. The topocentric distance to the fragment during observations varied from 36862 km to 37224 km at phase angles from 53 ◦ to 68 ◦ . The object’s brightness ranged from the 19th to the 21st magnitude. The parameters of the orbit and the brightness change diagrams are given.