The detached shear layer path was indicated by number 1. On the left side of Figure 1, the radar model is visualized, while on its right side, the flow starts to separate, and then reattach on the radar upper surface, but the viscous forces and shear layers are not strong enough. Figure 1 illustrates the flow behavior at the wake on a blunt body (radar), as explained in experimental research papers done on blunt bodies. The “ground surveillance radar” will be shortened by “radar” in the following sections. The “ground surveillance radar” in this study had the same characteristics as a blunt body while the wake region had a turbulent flow behavior. The reason is that the sharp edges of blunt bodies accelerate a transition to turbulent flow and a flow separation dominated by vortices and eddies. The boundary layer at the blunt body surface can be described in terms of flow separation, shear layers, vortex shedding, flow recirculation, and vortex formation, which may lead to a high surface drag coefficient. At the LARCASE, new methodologies in the aeronautical industry have been developed in the areas of actuated morphing wings and wing-tip systems, upper surface optimization of wing shapes for unmanned aerial systems, and Computational Fluid Dynamics models validations with experimental results from subsonic wind tunnel tests. The LARCASE laboratory is one of the few multidisciplinary aerospace research laboratories in Canada that has four pieces of state-of-the-art research equipment, such as a Cessna Citation X Business Aircraft Research Flight Simulator, a Bombardier series regional jet CRJ-700 Research Flight Simulator, an Autonomous Aerial System UAS-S4 from Hydra Technologies and a Subsonic Wind Tunnel Price-Païdoussis. The experimental tests were performed for the ground surveillance radar in the Price-Païdoussis subsonic wind tunnel at our Research Laboratory in Active Controls, Avionics and Aeroservoelasticity LARCASE. A procedure to quantitatively validate numerical models using experimental data from wind tunnel tests, including an analysis of a proposed “turbulence reduction system” is also part of this research. The proposed methodology employs a quantitative approach to analyze the wake region to evaluate the turbulence intensity, drag coefficient, pressure distribution coefficient, and boundary separation of a flow near a blunt body. A methodology to measure and analyze the flow characteristics near a full-size “Ground Surveillance Radar” without introducing probes into the flow field, that would affect its structure, to the best of our knowledge, has not been described in the literature. There are few studies, both in theoretical and in experimental research related to methods of studying flow behaviors in the presence of blunt bodies. Blunt bodies in turbulent flow conditions can lead to material fatigue and damage, and therefore, to increased drag and energy consumption. Most bodies and structures do not present a streamlined shape for this reason, an accurate analysis of wake regions would lead to a major understanding of turbulence flows and turbulence reduction mechanisms. The use of the proposed turbulence reduction system was found to be an effective way to reduce turbulent flow intensity by 50%, drag coefficients by 9.6%, and delay the flow transition point by 7.6 times.īlunt body flow analyses are very important in Engineering. A turbulence reduction system was proposed and analyzed in this research. A Computational Fluid Dynamics three-dimensional model was employed to analyze the wake region of the ground surveillance radar. Forces and moments were measured as functions of wind speeds and angular positions by the use of a six-component aerodynamic scale. A series of experiments were performed on a ground surveillance radar in the Price-Païdoussis subsonic wind tunnel. The main goal of this research was the development of a new methodology to analyze flows, and to measure flow characteristics without taking into account the distorting effects of measuring probes. Most experimental methods of flow studies use flow visualization and probes introduction into the flow field. An experimental and numerical investigation of the flow near a blunt body has been conducted in this study.
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