Mathematical Fluid Dynamics of Store and Stage Separation, Multi-Body Flows and Flow Control
Final rept. 1 Mar 2005-29 Feb 2008
TELEDYNE SCIENTIFIC AND IMAGING LLC THOUSAND OAKS CA
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New insights have been gained in atmospheric and space launch stage separation from our studies of the aerodynamic interference between multiple bodies in supersonic flow. Quick means of estimating and controlling repulsion or attraction lift is an important enabling technology to size launch separation rocket motors. Asymptotic methods, scattering, slender body theories and CFD modeling have provided valuable systematic approximations schemes that advantageously couple with modern computational methods. Our theoretical solutions for lift force interference between multiple bodies give good agreement with numerical solutions and experimental data. These solutions shed light on important scattering phenomena not previously recognized as relevant. The analyses allow us to identify lumped dimensionless parameters and provide scaling laws as well as closed-form expressions for the interference that can be used for interpolation and extrapolation of CFD solutions as well as efficient testing and design of new flight vehicles. This approach simplifies trajectory predictions in which inertial and aerodynamic forces are strongly coupled. There are cases when acceleration of the body C.G. andor the pitching angular velocity are not small and the unsteady effects become appreciable. First steps in mathematical modeling of these effects have been made. Typical phases of the transient process were identified. For each phase, analytical solutions of the flow potential and wave drag were obtained. The transient process was also simulated numerically by solving 3-D Euler equations. The theoretical wave drag is in excellent agreement with CFD in all phases of the transient process. These results provide a good launching pad for theoretical modeling of unsteady body motions including the coupling between body dynamics and aerodynamics.
- Fluid Mechanics
- Spacecraft Trajectories and Reentry