Перегляд за Автор "Semenenko, V."

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  • Ескіз
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    Dynamics of supercavitating vehicles with cone cavitators
    (Igor Sikorsky Kyiv Polytechnic Institute, 2022) Semenenko, V.; Moroz, V.; Kochin, V.; Naumova, O.
    The work is devoted to theoretical and experimental investigations of dynamics of high-speed underwater supercavitating vehicles with cone cavitators. The cone cavitators are considered as operating controls of the supercavitating vehicle motion. The mathematical model of a “slender” unsteady cavity based on the G.V. Logvinovich principle of independence of the cavity section expansion is used. Experimental studies of the rotary cone cavitators were carried out at the high-speed experimental tank of the Institute of Hydromechanics of the NAS of Ukraine. Based on test results, the approximate dependences of both the drag coefficient and the lift coefficient of an inclined cone cavitator on the rotary angle in a wide range of cone angles are proposed. The range of cone angles is determined when the cone cavitators are the more effective operating controls in comparison with equivalent disk cavitator. With the help of computer simulation, a number of problems of dynamics of the supercavitating vehicle with cone cavitators were investigated: balancing the vehicle, the motion stabilization, maneuvering the vehicle, the cavity control. For the first time, experimental verification of the mathematical model of the supercavitating vehicle dynamics “as a whole” was performed by testing the model with cone cavitators and cavity-piercing fins with a degree of freedom in pitch.
  • Ескіз
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    Formation and development of ventilated supercavity past the disk–cavitator in accelerated motion
    (Igor Sikorsky Kyiv Polytechnic Institute, 2023) Moroz, V.; Kochin, V.; Semenenko, V.; Naumova, O.
    Аbstract. The work is devoted to both the experimental studies and the computer simulation of the process of formation and development of a ventilated supercavity past the disk-cavitator in accelerated motion from the state of rest to the steady velocity. A series of experiments were carried out in the high-speed experimental tank at the Institute of Hydromechanics of the National Academy of Sciences of Ukraine for various values of the air-supply rate into the cavity. It has been established that the portion type of air-loss from the cavity is always preserved in the case of horizontal accelerated motion, while the air-loss by vortex tubes is always realized in the case of steady motion with the same velocity. In this case, shape of the cross sections of the unsteady cavity is close to circular one along the whole cavity length and at all stages of acceleration. To describe this process, a modified mathematical model is proposed that is based on the G.V. Logvinovich principle of independence of the cavity section expansion. An analysis of the influence of both the immersion depth and the air-supply rate on the process of development of a ventilated supercavity during acceleration has been performed by the way of computer simulation.