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Information × Registration Number 0225U000082, (0122U000800) , R & D reports Title Investigation of hydrodynamics and stability of unsteady motion of bodies when crossing the free boundary of liquid in the regimes of supercavitation and unsepatated flow popup.stage_title Проведення експериментальних та фізичних досліджень суперкавітаційних та безвідривних течій. Порівняння експериментальних результатів з розрахунками на основі математичних моделей. Head Savchenko Yurii M., д.т.н. Registration Date 04-01-2025 Organization The Institute of Hydromechanics of the National Academy of Sciences of Ukraine popup.description1 Performing of experimental and theoretical researches of features of unsteady supercavitation and unseparated flows when crossing the free boundary of liquid and in the high-speed motion of bodies near solid and free surfaces for the purpose of their optimization and improvement of control methods popup.description2 A pneumatic catapult was modernized and method for experimentally studying the water entry and penetration of models at small angles to the horizon was developed. By processing the filming frames, graphs of the experimental time dependence of the model velocity and flown distance were obtained. According to the test results, four types of dynamic behavior of models were distinguished depending on starting conditions: penetration along a straight path; penetration with the path deflection; deep ricochet; model overturning. Computer simulation of the processes of water penetration of models at small angles to the water surface was performed. Comparison with experiments shows that the adopted mathematical model adequately describes the main features of hydrodynamic processes. Principles of choosing the optimal shapes of hulls of ground, air and water vehicles to achieve maximum range were considered. Formulas for the economic efficiency of automobiles, airplanes, air and sea gliders, CABs, rotorcraft, airships, boats and submarines are given, examples of choosing optimal characteristics are given. High values of economic efficiency open up prospects for achieving a long range even when using electric motors, obtaining a range from 410-850 km for airplanes, 420-50km for CABs dropped from height 10km, 800-1200km for underwater and surface vehicles and practically unlimited stay in the air of airships powered by solar energy. A completely nonlinear solution of the problem of flow over a circular cylinder with free boundary taking into account surface tension is given. The integral hodograph method allows reducing the boundary value problem with boundary conditions to a set of integral equations. These equations are formulated in terms of the velocity magnitude at the free boundary and the cylinder surface inclination and will be solved numerically using the collocation method. Position of the free boundary separation line is determined by the Brillouin–Villat criterion. Product Description popup.authors Ivaniuk Volodymyr F. Vlasenko Yurii D. Kozenko Oleh M. Manova Zinaida I. Naumova Olena I. Nesteruk Ihor H. Savchenko Heorhii Yu. Savchenko Yurii M. Semenenko Volodymyr M. Semenov Yurii A. Temerov Anatolii S. popup.nrat_date 2025-01-04 Close