Determination of aerodynamic characteristics of rotating aircraft in the uncontrolled flight by means of engineering analysis systems
Aeronautical and Space-Rocket Engineering
Air force academy named after professor N.E. Zhukovskii and Yu.A. Gagarin, 54a, Starykh bol'shevikov, Voronezh, 394064, Russia
In this work the standard software package on ANSYS CFX hydraulic gas dynamics is used for calculation of aerodynamic characteristics (coefficient of front resistance) of the rotating aircraft (A).
Currently, mathematical modeling methods are used for the determination of the aerodynamic characteristics for a wide range of aircraft. The main advantage of calculated methods is that once properly developed mathematical model and the program can be used repeatedly in different variants of the aircraft assembly scheme, which provides prompt problem resolution of determining aerodynamic characteristics.
This paper considers the simulation of the gas flow around the rotating smooth bodies based on accurate finite-difference method in a computing environment ANSYS CFX. The algorithms for solving the Navier- Stokes equations for the flow space, axisymmetric bodies by viscous gas on the basis of a complete system of equations that allows you to calculate the coefficient of drag of rotating aircraft for different Mach numbers and calculate the change in this ratio for the given angle of attack, which at the stage of setting the geometry of the computational domain is defined by the angular position of rotating aircraft relative to the oncoming flow.
Comparison of simulation results with field experiments performed, showed that the convergence in determining the drag coefficient is within the range of 5%.
Considered is the question of the influence of the rotational motion of the center of mass on the flight of uncontrolled aircraft. For that purpose, on the basis of the calculated data of drag coefficient of rotating aircraft with angles of attack other than zero method of least squares, allowed obtain the dependence of the ballistic coefficient of the angle of attack.
Thus, using the obtained dependence of the ballistic coefficient from the angle of attack it is possible to account the angular perturbations when calculating the parameters of the rotating trajectory aircraft.
Keywords:rotating aircraft, ballistic coefficient, angle of attack, drag coefficient, finite element analysis
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