Identification of Gas Properties via Measurements of Absorbed Heat Flux

This paper considers the features of solving the problem identifying characteristics of a gaseous medium via measurements of the heat flux absorbed by the surface of a blunt body in a supersonic flow. Three groups of parameters are distinguished identification of which is feasible from known values of surface temperature and heat flux: thermodynamic properties of the gaseous medium, its transport properties and conditions on the outer boundary of the boundary layer. In this paper, the transport properties of the gaseous medium are considered as an object of identification. The study is carried out within the framework of the perfect gas model. The identification problem is formulated in the extremum setting. For optimization, the Nelder–Mead method is used in combination with random restarts. It is shown that owing to the specificity of the structure of a set of points the objective function value in which is lower than the value specified by the accuracy of the heat flux measurements, it is possible to obtain a fairly accurate estimate of the identified parameters.