Multi-disciplinary Modelling of the Aerothemodynamically-induced Fragmentation of Re-entering bodies
The prediction of atmospheric re-entry is impacted by the fragmentation of the re-entering objects as a result of severe aerothermal loads. Improved models of the aerothermodynamically-induced fragmentation will be formulated to assess the risks associated to re-entry.
Accurate modelling of the break-up mechanism of re-entry objects is quite challenging due the its complexity and multi-disciplinary nature. In fact, the unsteady changes in the object shape and the computational domain and the changes in the aerodynamic environment consequent to the relative motion of fragments will substantially affect the aerothermal loads in the first instants after the separation. Existing modelling and simulation capabilities are still based on simplifying assumptions that cannot address in a consistent manner the break-up process and this results in a substantial degree of uncertainty.
In order to reduce the uncertainty on the overall demise process, it is here proposed to:
1) develop an approach based on high-fidelity methods with adaptive meshing to model the aerothermodynamics of the initial instants of fragmentation;
2) use peridynamics to model fracture initiation, propagation and fragments detachment leading to changes in the topology of the computational domain around the re-entering object(s) / fragments;
3) couple the high-fidelity approach with a 6 DoF model of the object motion to account for the impact of the separation on the dynamics of proximal fragments;
The high-fidelity model of the few seconds before and after the break-up will be coupled with and existing low-fidelity model of the atmospheric entry and descent. The expensive but accurate high-fidelity approach will be invoked to model the few instants before and after the fragmentation and detachment. When fragmentation is not happening and/or fragments are sufficiently far from each other such that no interaction takes place, a low-fidelity approach will be used. A loose coupling approach between low- and high-fidelity approaches will be formulated to transfer loads and geometrical definitions. In this way an optimal trade-off between computational cost and accuracy can be achieved and the uncertainty on the demise process coming from inaccurate predictions of objects fragmentation eventually reduced.
Co-sponsored project with the European Space Agency, Lockheed Martin, Fluid Gravity and University of Strathclyde.
- UK or EU nationality
- Background in Computational Aerothermodynamics
- Degree in Aerospace Engineering or Applied Physics
The award will cover Home/EU tuition fees, and provide a monthly stipend for the 3 year period of study. The total stipend for academic year 2019/20 is £15009 (subject to increase).
Please forward CV and up to date transcript to [Email Address Removed]