Авіаційно-космічна техніка та технологія (Feb 2018)
COMPLEX METHOD FOR CALCULATING THE FRICTION RESISTANCE AND THERMAL REFRACTION ON THE SURFACE OF FLIGHT AXISYMMETRIC OBJECTS ON FLIGHT BY TRAJECTORY WITH AVAILABILITY IN THE WALL BOUNDARY LAYER NON-ISOTHERMAL, COMPRESSIVE, LAMINAR-TURBULENT TRANSITION AND
Abstract
The complex method of calculation of aerodynamic resistance of friction and heating on the surface of flight axisymmetric bodies of rotation like a jet uncontrollable shell is developed. The method allows to carry out calculations from the moment of start to landing in limits to-, a trance- and supersonic speeds of flight. Range of speeds corresponds to М∞ ≤ 3,0 Mach numbers. When calculating the phenomena of a non-isothermicity, compressibility, laminar-turbulenttransition and a relaminarization which occur on streamline surfaces when flying on a trajectory are considered. The method is based on use of the asymptotic theory ofa wall turbulent boundary layer ofS.S. Kutateladze and A. І. Leontyeva in combination with results of the linearized theory of flow of bodies of rotation, the theory of turbulent spots of Emmons of a transitionalboundary layer and data on Reynolds numbers of the beginning of laminar-turbulenttransition received by results of flight experiments. On the basis of the carried-out calculations of parameters of a stream on a streamline surface of a shell when flying on a trajectory from the moment of start to landing in limits to-, a trance- and supersonic speeds of flight with use of the boundary numbers of laminar-turbulent transitionreceived in flight experiments it is established that flow of a considerable part of a surface of a shell happens in the conditions of laminar-turbulent transition and a relaminarization which occupy an essential part of the general time of flight. Existence of a reverse of laminar-turbulent transition is established by a settlement way. The analysis of values of temperature on a surface of a head part of a rocket when flying on a settlement trajectory has shown that for rather short period there is an aerodynamic heating of a surface which significantly influences the aerodynamic resistance of friction by a non-isothermicity in a wall boundary layer. The conclusion is drawn that the linearized theory of calculations of flow of rather thin bodies of rotation can be used for calculation of parameters on external border of boundary layer of axisymmetric bodies of rotation like a jet uncontrollable shell in limits to-, a trance- and supersonic speeds of flight for the purpose of account longitudinal to pressure gradient when calculating friction and heating. Use of the linearized theory of flow for calculation of parameters on external border of boundary layer in limits to-, a trance- and supersonic speeds of flight allows to create a "fast" algorithm of calculation of resistance of friction and heating taking into account a longitudinal gradient of pressure existing on the streamline surfaces of axisymmetric bodies of rotation. Numerical results of calculations of parameters of a nonviscous current on external border of boundary layerfor the linearized theory, coefficient of a intermittency, temperature of heating of a surface of a shell and resistance of friction from the start moment before landing are given
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