Авіаційно-космічна техніка та технологія (Apr 2019)
CALCULATION OF THE AERODYNAMIC CHARACTERISTICS OF SUPERSONIC AXISYMMETRIC FEATHERED BODIES OF ROTATION
Abstract
The subject of research in the article is the aerodynamic forces arising from the flight of supersonic feathered rotation bodies such as unguided rockets. The aim of the work is to develop a method for calculating the aerodynamic coefficients of the resultant forces and moments of supersonic feathered bodies of revolution such as unguided missiles when flown around at an angle of attack with pre-, trans- and supersonic speeds according to drawings of their external contours. Tasks: using modern software systems and flight experiments, develop a method for calculating the distribution of normal and tangential stresses over the surface of a supersonic feathered body of rotation, their equivalent and aerodynamic coefficients at up-, trans- and supersonic flow velocities at an angle of attack. The applied methods are the numerical solution of the Navier-Stokes equations, the use of two-parameter differential models of near-wall turbulent viscosity, verification of the methodology by comparing the results of calculations with the data of flight experiments and known data on the aerodynamic resistance of the object of research. The following results were obtained. Based on the numerical solution of the Navier-Stokes equations in the ANSYS CFX software package using the γ-ReΘt SST–model of Menter’s near-wall turbulence, a method is developed for calculating the aerodynamic characteristics of supersonic axially symmetric rotation bodies of uncontrollable missiles according to drawings of the external contours in the presence of a counter-flow angle. Using the developed technique it is possible to calculate the aerodynamic coefficients of friction resistance, pressure resistance and bottom resistance at sub-, trans- and supersonic speeds. Characteristics include the coefficients of the longitudinal aerodynamic force, transverse aerodynamic force, aerodynamic stabilizing moment and the coordinate of the center of pressure of the feathered body of rotation. For the calculations, were applied the external contours of the unguided missile M–21OФ. Calculations were performed for the counter-flow Mach numbers within0,1 £ M∞ £ 2,5. The aerodynamic coefficients were calculated as functions of the Mach number M∞. In order to determine the Reynolds number of the beginning of the laminar-turbulent transition in the boundary layer for this type of aircraft the characteristics of the friction resistance were calculated and compared with the flight data for two samples of research aerophysical complexes. Conclusions. The scientific novelty of the results is as follows: a pilot test was created and involved the results of flight experiments on Reynolds numbers of the start of a laminar-turbulent transition in the boundary layers of a method for calculating the aerodynamic drag coefficients of supersonic axially rotated bodies of rotation like uncontrollable missiles according to the drawings of their external contours during turning angle of attack based on the numerical solution of the Reynolds-averaged Navier-Stokes equations in the framework of the programme product ANSYS CFX using γ-ReΘt SST–Menter turbulence model. Verification of the calculation results was carried out on the basis of their comparison with the known values of the aerodynamic characteristics of the object of research with the axisymmetric flow.
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