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The axisymmetrical model in the test section of the T–38 wind tunnel
Source publication
Test of the flow field around the axysimmetrical body – model of the torpedo without fins and control surfaces, was performed in the trisonic wind tunnel of the Military Technical Institute (MTI), for the speed of undisturbed flow which corresponds to the Mach number . Aerodynamic forces and moments were measured by six-component internal strain ga...
Citations
... For all flow visualization methods, an appropriate approach to record the image, such as taking photos or recording videos, is necessary. Profiting from computer techniques, it is possible to analyze flow visualization automatically and achieve qualitative and quantitative information by digital image processing [22,23], which is not easy for conventional flow measurements [24][25][26][27]. Vey et al. [28] established a measurement technique which allows extracting quantitative data from tuft flow visualization on real-world wind turbine blades. ...
... Aerospace 2022, 9, x FOR PEER REVIEW 2 of 13 achieve qualitative and quantitative information by digital image processing [22,23], which is not easy for conventional flow measurements [24][25][26][27]. Vey et al. [28] established a measurement technique which allows extracting quantitative data from tuft flow visualization on real-world wind turbine blades. ...
The luminescent mini-tufts method is widely used for flow visualization for quantitative field analysis. A set of numerical methods for digitalization of 3D surfaces surrounding flows with luminescent mini-tufts has been developed in this study. The procedure includes digital image pre-processing, mini-tufts recognition, mean field mini-tufts calculation, inclination angle calculation, oscillation area calculation, etc. The model is subjected to a newly proposed digitalization method and realized by in-house code. The time mean angle’s changing mode, along the mini-tuft, are analyzed, which shows that the mini-tuft follows the inflow well. The transient oscillation of mini-tufts is observed as well, which shows that on the middle part of the irregularity cylinder, the flow oscillates more intensively.
... a b Fig. 9: Flow visualization with fluorescent tufts in subsonic wind tunnel (flow is left to right)[18]4. SURFACE FLOW VISUALIZATION METHODSFor observation of flow characteristics close to the wall of a model, the body wall can be coated with a certain material which indicates the local wall temperature, surface pressure, or the streamline pattern of flow adjacent to the wall[1][2][3][4][5][19][20][21][22]. ...
Flow visualization is an important topic in, experimental and computational
fluid dynamics and has been the subject of research for many years. This
paper presents an overview of flow visualization techniques. The physical
basis and applications of different visualization methods for subsonic,
transonic and supersonic flow in wind and water tunnels are described:
direct injection methods, (smoke, dye, fog and different small particles),
gas and hydrogen bubbles, , flow visualization by tufts, oil, liquid
crystals, pressure and temperature sensitive paints, shadow, schlieren,
interferometry, Laser Doppler Anemometry, Particle Image Velocimetry and
other special techniques. Almost all presented photos have been recorded
during tests in laboratories of MTI Belgrade.
... The advent of computer technique and digital image processing make it possible to automatically analyze flow visualization effects and extract qualitative and quantitative information, which may not be readily available from conventional flow measurements [1,5,12,21,23,30,32,36,38]. Recently, a new type of visualization has emerged: computer-aided visualization. ...
In this article, an attempt is made to describe and review the most widely used methods for flow visualization. The first part describes the basis and applications of different visualization methods (non optical) for subsonic and supersonic flow in wind and water tunnels: direct injection methods, (smoke, dye, fog and different small particles) visualization methods by electrolytic and photochemical dye production, gas and hydrogen bubbles, special techniques, flow visualization by tufts, oil, liquid crystals, pressure and temperature sensitive paints. A considerable attention is paid to flow visualization techniques performed in VTI wind and water tunnels and almost all presented photos have been recorded during tests in laboratories of VTI. Optical methods and their application for compressible flow visualization will be given in the second part of the article.
