Calculation of aerodynamic characteristics of a recoverable carrier-rocket core stage of the Soyuz-2-1a type in modeling its disturbed motion

Using the CAE system Ansys Fluent, a numerical solution was obtained for the aerodynamics problem of a recoverable carrier-rocket block whose prototype is the central core of the Soyuz-2-1a launch vehicle, on the descent segment to Earth. At each time step of the integration of the spatial motion equations, an algorithm for computing aerodynamic coefficients is implemented: the motion-integration module calls Ansys Workbench to solve a steady gasdynamic problem by the finite-volume method. The procedure includes construction of the computational domain geometry, mesh generation, specification of the physical model and boundary conditions in Ansys Fluent, and extraction of lift, drag and side forces as well as moments as functions of angle of attack. Plots of the steady aerodynamic coefficients versus angle of attack were obtained and used in models of the free uncontrolled motion of the block after separation. Using the refined aerodynamic coefficients at each integration step, an integral trajectory calculation was performed accounting for wind loading, which made it possible to estimate the expected coordinates and impact areas. The presented methodology enables obtaining refined motion trajectories, accounting for non-axisymmetric configurations and, in future work, incorporating structural elasticity to improve prediction accuracy and reduce potential environmental harm.