Shock Tube Experiments for Earth and Mars Entry Conditions
In-depth knowledge of gas dynamics at hypersonic speeds is required to define the environment and requirements for the design and safe operation
Publication Reference: RTO-EN-AVT-162DOI: 10.14339/RTO-EN-AVT-162-13-doc Download View All Papers View Meta Data Share
Abstract: In-depth knowledge of gas dynamics at hypersonic speeds is required to define the environment and requirements for the design and safe operation of space vehicles, planetary probes, and rockets. Development of physical models and numerical methods has enabled major advancements in our approach to the design of vehicles, and has minimized the needs for extensive flight tests. However, there remain many challenges in our ability to model the hypersonic regime. Transport of mass, momentum, and energy in hypersonic flows in thermo-chemical non-equilibrium requires further development of the physical models and reliable experimental data to guide and validate these models. The complexity of the physics in the hypersonic regime presents unique challenges for measurement techniques and flight tests. The objectives of the lecture notes were to review the up-to-date physical models describing complex high-enthalpy and non-equilibrium effects, measurement techniques for flight test and ground-based experiments, as well as numerical simulation strategies specific to the hypersonic regime, focusing, in particular, on the accurate prediction of the thermal loads on atmospheric entry bodies. The first part of the notes addresses theoretical issues of irreversible thermodynamics and kinetic theory of plasmas and reactive molecular gases, including a note devoted to the specific treatment of electronic excited states. Dissociation cross sections and reaction rate coefficients for nitrogen computed from first principles are then presented, as well as two reviews on the electron impact excitation and ionization in air and carbon dioxide mixtures. Subsequent lecture notes deal with shock-tube and shock tunnel design and experiments, with particular emphasis on optical diagnostics. Radiation databases and modeling, as well as collisional radiative models are also presented for both shock-tube experiments and simulations of Earth and Mars atmospheric entries. A new approach to risk-based analysis and testing deals with quantification of uncertainty in flow simulations using probabilistic methods. The frontiers of aerothermo-dynamics are then described, giving directions of future research. Finally, the lecture notes are devoted to advanced numerical methods for hypersonic flows, covering both computational fluid dynamics and direct simulation Monte-Carlo methods.
Author(s): Bogdanoff, D.W.
Publication Reference: RTO-EN-AVT-162
Publication Identifier: RTO-EN-AVT-162 AC/323(AVT-162)TP/279
ISBN (if applicable): ISBN 978-92-837-0091-3
Classification: PUBLIC RELEASE
Access: Open Access
Subjects: Fluid Mechanics - Phenomenological and Experimental