Ing Ind - Inf (Mag.)(ord. 270) - BV (469) AERONAUTICAL ENGINEERING - INGEGNERIA AERONAUTICA
054230 - FUNDAMENTALS OF HYPERSONIC FLOWS
Hypersonic flows are characterized by high intrinsic kinetic energy which, during the interaction with bodies immersed within the gas stream, can be transferred to several physical processes, depending on the flow regime. Such processes include excitation of high vibrational levels, chemical reaction, ionization and emission of radiation. Each of the listed process is still subject of intensive research activities whose comprehensive treatment cannot be given by a single course. Hence, the course aims at presenting the most basic aspects of the phenomena which govern the physics of high temperature gases and assessing their importance in the different flow regimes encountered, for instance, during planetary entry manouvres of space vehicles.
Risultati di apprendimento attesi
It is expected that, at the end of the course, the student has acquired:
1) A clear understanding of the most basic processes involved into the physics of high temperature gases.
2) A clear understanding of the basic mathematical/numerical models that allow predicting (to some extent) the properties of hypersonic flows.
1 - Elements of molecular structure. 2 - Kinetic theory of dilute gases: dynamics of molecular collisions, the Boltzmann equation, the H-theorem, the partition function and thermodynamic equilibrium properties of a mixture of gases. Small and large Knudsen numbers: the aerodynamics of bodies in low earth orbit, Euler and Navier-Stokes approximation. 3 - Inviscid equations for a gas with roto-vibrational internal degrees of freedom. Local equilibrium approximation, vibrational relaxation rate equations. Shock wave structure, flows around blunt bodies.
4 - Inviscid equations for chemically reacting flows. Local equilibrium approximations, chemical rate equations. The ideal dissociating gas. Models of high temperature air chemistry.
5 - Flows with translational non-equilibrium and high altitude flight. Introduction to the Direct Simulation Monte Carlo (DSMC) method with simple applications to entry flows.
1) OpenFoam applications to hypersonic flows around simply shaped bodies with different gas models
2) DSMC applications to hypersonic flows in the rarefaction regimes.
It is expected that students have a solid knowledge of the fundamental concepts about fluid dynamics and gas dynamics. In particular, the knowledge of inviscid, compressible flow equations for a simple polytropic gas and their applications to shock waves is assumed as starting point.
Modalità di valutazione
The examination is divided into two steps. The first one consists into a written test containing a number of questions concerning the basic concepts exposed during the course. The second step consists of the oral discussion of a simple numerical simulation run by the student. The access to the second step requires that the minimum threshold of 18/30 is reached in the first one.
John D. Anderson, Hypersonic and High-Temperature Gas Dynamics, Editore: American Institute of Aeronautics and Astronautics, Anno edizione: 2006
Ernst Heinrich Hirschel, Basics of Aerothermodynamics, Editore: Springer, Anno edizione: 2014
W.G. Vincenti, C.H. Kruger, Introduction to Phyisical Gas Dynamics, Editore: Krieger Publishing Company, Anno edizione: 1986
J. H. Ferziger, H. G. Kaper, Mathematical Theory of Transport Processes in Gases, Editore: North Holland Publishing Company, Anno edizione: 1972 Note:
Out of print. A .pdf version will be made available.
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Tipo Forma Didattica
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Ore di studio autonome
Laboratorio Di Progetto
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