RESEARCH AREA
: Supersonic motion of bodies through gases and two-phase media.
During the past 20 years the unique experience of free flight tests aimed at study of flight performance (stability, drag, etc.) of various objects in the area of ordnance, rocket and space technology has been accumulated (Dr. A.N. Mikhalev). Investigations are performed so as to evaluate aerodynamic characteristics of a body under study. A special advanced technique of non-linear estimation, including mathematical statistics approaches, is employed (Dr. N.P. Mende and Dr. A.B. Podlaskin). The static aerodynamic coefficients are determined with accuracy of 1-5%, the damping moment is found with accuracy of 5-10%. Among the objects studied there are various projectiles of classical sharp and blunt bodies (including spacecraft Soyuz command module), bodies with a region of spike-induced flow separation (like Trident missile), models of explosively formed projectiles and so on.
Along with estimations of aerodynamic forces and momenta, our instrumentation allows us to obtain large-scale shadowgraphs and interferograms of flows over flying projectiles. This gives us possibility to study specific features of the flows and reconstruct gas density distributions over bodies of revolution. To deal with 3D flows, several interferometric projections should be processed together. In 1978-1981 an optical tomograph including five shearing (polarization or grating) interferometers at the same cross-section of the ballistic range was successfully operated. Another way to get appropriate data is to use one interferometer in a series of experiments with the same object under study positioned at different angles to the optical system axis (for steady flows). For data processing of the set of the interferometric projections of aerodynamic objects special software (Dr. N.P. Mende and Dr. A.B. Podlaskin) is used. High level of the optical measurements and data processing result in high accuracy of reconstructed gas density fields that are used for validation of CFD results.
During the last 8 years the study of supersonic body motion through two-phase media has been conducted (Dr. P.I. Kovalev). Unique results have been obtained when studying motion of bodies through dusty air and interaction between a supersonic sphere and free falling water drop. Among them are: conclusions on formation of a dusty trail behind a flying sphere; elucidation of solid particle crushing and reflection mechanism in high-speed collision between a solid surface and a particle; records of shock wave structure after impact of supersonic sphere to water drop.
The Group has accumulated great experience in designing and constructing diagnostic and auxiliary equipment for ballistic research including optical and electronic (synchronization) systems, spark light sources, powder propulsion systems for aerodynamic investigations. The recorded images of flow patterns are processed with the help of an automated computer-based system delivering initial data in appropriate format for further mathematical processing.
1. A ballistic range with powder guns of 24, 35, 57 mm in caliber (the projectile velocity up to 1500 m/s) and the test chamber of 1 m in diameter, 15 m in length equipped by:
2. A ballistic set-up for study of supersonic body motion through two-phase media with the powder guns of 24-35 mm in caliber and the test chamber dimensions of 0.4 x 0.4 x 0.5 m equipped by:
3. A shock tube of an explosive type with varying shape of the working section equipped by a two-frame grating interferometer.
In all the cases above the optics provide natural scale (1:1) shadowgraphs and interferograms.
4. Instrumentation for a data processing (computer hardware and special software system).
All the software used for data processing was elaborated in the Group.
Ballistic Research Group consists of 6 researchers (including 4 PhD) and 1 technician.
The Group as a whole is headed by Dr. N.P.Mende
The possible forms of collaboration with the Group are either conducting investigations of high-speed aerodynamic and other processes at our facilities using optical recording systems or participation of Group members in elaboration of the experimental diagnostic equipment and software applications for the ballistic experiment at other facilities.
NEW!
Recenty published: An Album of pictures, accumulating the experimental results of the Ballistic Research group of the last 20 years.
