Image intensity as a quantitative aspect of gas flow parameters

Aerodynamics and heat-exchange processes in flying vehicles


Аuthors

Bodryshev V. V.*, Abashev V. M.**, Tarasenko O. S.***, Mirolyubova T. I.****

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: soplom@mail.ru
**e-mail: kiriger@gmail.com
***e-mail: os-tarasenko@yandex.ru
****e-mail: olgaiskra@yandex.ru

Abstract

The article addresses a method of digital processing for gas flow photos. It gives numerical analysis using the criterion of image intensity at all gas flow stages (before compression shock, in the compression shock and beyond it). Laws of variation of image intensity values are seen to be correlated and depend on the streamlined body shape and initial flow rate.

Quantitative parameters of image intensity which characterize the gas flow in compression shocks and wave flow areas were identified using linear regression analysis.

In case of “horizontal” gas wave flow, the arithmetic mean deviation of intensity was selected as a determining parameter. In case of several compression shocks, the arithmetic mean of the difference between the maximum and minimum intensity values in the compression shock was selected as a criterion. For the “inclined” gas wave flow, the arithmetic mean deviation of intensity relative to the regression line was selected as a determining parameter. The mathematical apparatus for calculation of suggested criteria is offered.

Keywords:

supersonic gas dynamic flow, experimental studies, image intensity, visualization methods, shadow photograph digital processing, shock-wave process, correlation coefficient

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