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Information × Registration Number 0216U008289, 0114U002435 , R & D reports Title Development of applied models for supercavitating, jet and near wall flows popup.stage_title Head Savchenko Yurii Nikolaevich, Registration Date 22-12-2016 Organization The Institute of Hydromechanics of the National Academy of Sciences of Ukraine popup.description2 A numerical-analytical solution of the self-similar problem of the expanding cylinder penetration into liquid is presented. Application of the integral hodograph method allowed obtaining an expression for the complex velocity and the derivative of the complex potential, which includes a free parameter characterizing the expansion velocity of the cylinder. With the use of kinematic and dynamic boundary conditions, the problem is reduced to a system of integral equations, which was solved numerically by the method of successive approximations. The configurations of the boundary and pressure distribution on the cylinder for different speeds were obtained. The mathematical model of three-dimensional dynamics of automotive partially cavitating underwater vehicles (PCV) was developed and computer simulations were carried out. Calculations showed that in comparison with the longitudinal movement of supercavitating underwater vehicles (SCV) in planning mode in the cavity, the movement of PCV is stable with respect to vibrations of the pitch angle. It was established that transverse components of the inertial force, which arise on the wetted part of the hull, and its torque with respect to the center of mass relative are the damping factor for PCV. At the same time, components of buoyancy and hydrodynamic forces and their torques can destabilize the movement. During the acceleration the deviations of parameters depend on the degree of the initial imbalance of CV and can become unacceptably large. Thus, the movement of both PCV, and SCV requires additional stabilization. It was shown that at constant speed of movement and during the acceleration and deceleration, the same system of automatic control as for SCV can be successfully applied. The analytical solution of the equation for the form of the slender steady axisymmetric ventilated cavity at high Froude numbers was obtained and its features were analyzed. It is shown that the gas injection can both increase and decrease the size of the cavity. For the first time the existence of neutral forms of the hulls, providing constant cavity shapes at any injection intensity, was revealed. Examples of calculations of the cavity shapes on different hulls are presented. It was shown that the cavity may have not only the classic elliptical shape, but may also be conical, hyperbolic, parabolic and cylindrical. Their radius can also attain minimum. The condition in which the cavity length may change abruptly, when passing through a discontinuity of the hull shape was found.5481 Product Description popup.authors Іванюк Володимир Філімонович Власенко Юрій Дмитрович Каширіхін Леонід Петрович Козенко Віктор Феодосійович Козенко Олег Миколайович Козенко Роман Миколайович Криницький Володимир Олександрович Манова Зінаїда Іванівна Наумова Олена Іонівна Нестерук Ігор Георгійович Савченко Георгій Юрійович Савченко Юрій Миколайович Семененко Володимир Миколайович Семенов Юрій Асаф'євич Чичик Петро Дмитрович popup.nrat_date 2020-04-02 Close