Aircraft safety depends on wing flow process, so the study of air flow in different flight conditions is one of the most important parts of aircraft design and exploiting. The effective method of aerodynamic processes modeling is experiment in wind (aerodynamic) tunnel or water (hydrodynamic) tunnel. They allow to perform experiments with a scaled model of an aircraft affected by icing and to visualize the wing flow process and changes caused by icing. A visualization and video registration of the wing flow yields useful qualitative information about flow, but it is more important to retrieve quantitative 3D data of flow for 3D visualization and analysis. The presented study addresses to creating an image-based system for accurate 3D flow acquisition for further diverse 3D visualization and quantitate evaluation of 3D flow parameters in a hydrodynamic tunnel for aircraft icing influence exploration. Being an initial part of a long- term research project, this study is aimed at developing stereolithography (SLA) modeling technique for flow visualization in hydrodynamic tunnel and a photogrammetric system for accurate flow 3D caption. The results of first experiments of the system calibration and application are given along with preliminary results of flow jets 3D reconstruction.

Abstract. Aircraft icing is one of the main factors decreasing the flight safety. Qualitative and quantitative understanding of the icing process is crucially needed for developing anti-icing measures and safety recommendations. Changes in aerodynamic characteristics of aircraft caused by changes in shape of aircraft surfaces due to the ice accretion can lead to significant aerodynamic performance degradation. So the reliable and accurate information of how the shape of the ice accretion influences on aerodynamic characteristics is a key point for predicting the changes in aerodynamic performance.The study addresses to a problem of accurate shape measuring of ice accretion for further experimental study of iced-aircraft aerodynamic in a hydrodynamic tunnel. For this purpose the evaluation of various techniques of ice 3D measurements is performed that include as visible so thermal imaging of ice accretion. The results of evaluation serves for the decision of preferable technique to be used in experimental study. Also the framework is developed for creating physical models of iced aircraft based on result of real ice accretion shape measurement. It allows to produce stereolithography (SLA) copies of of an aircraft under icing condition for different levels of icing. These SLA-models of an aircraft under icing condition are then used for flow behaviour study in order to identify critical flying condition.

Abstract. Hydrodynamic tunnel has proved to be an effective mean for studying aerodynamic processes using scaled models of real aircrafts. The specificity of study in a hydrodynamic tunnel requires to apply non-contact measuring techniques, such as photogrammetry, for retrieving information on geometrical characteristics of the flow. So reliable calibration of photogrammetric system is a key element for trustworthy analysis of flow behaviour. For 3D measurements in a hydrodynamic tunnel calibration technique must account for refraction effects at optical media interfaces. But often the design of a hydrodynamic tunnel does not allow to perform standard calibration procedure based on image acquisition of a special test field, placed in the working space of the measuring system. The presented study addresses this problem – developing the technique for accurate photogrammetric calibration, for the case of the working space being inaccessible for placing there a test field. The developed calibration technique estimates parameters of interior orientation of the photogrammetric system and parameters of multimedia optical environment by special preliminary procedure, that allows to obtain accurate 3D measurements during experiments in hydrodynamic tunnel. Experimental evaluation of the developed technique demonstrated high accuracy of photogrammetric 3D measurements.