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In the present study, the ventilation performance of a one-sided wind-catcher positioned in the wake of an upstream structure is experimentally investigated by measuring the induced airflow rates and employing smoke flow visualization techniques. Wind-catchers are usually used in places of high urban densities in Middle East regions; however, their potential to provide natural ventilation depends on the presence of upstream structures. The present study focuses on the ventilation performance evaluation of a one-sided wind-catcher located in the wake of an upstream structure model. The influence of the upstream structure height and its distance relative to the wind-catcher on the flow structure within and around the wind-catcher is investigated. Moreover, the ventilation performance is evaluated by measuring the ventilation flow rate using a hot wire anemometer for upstream air velocities of 10 and 15 m/s. The results show that the presence of an upstream object influences the rate and the direction of air flowing from the wind-catcher to the house. Placing a short upstream object increases the induced air flow rate. However, by increasing the height of upstream object, the airflow direction is reversed inside the wind-catcher and the air may flow backward from the ventilated space to the wind-catcher.

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The flow field around the axisymmetric streamlined bodies which forms the main body of the airplanes and submarines has been the subject of several researches. The present study aimed to investigate the flow field around a standard submersible model in various angles of attack by employing two visualization methods. The vortex structures around the model are qualitatively studied at the 40-degree angle of attack in a vertical wind tunnel. These structures are visualized by the laser sheet illumination of the smoke injected flow. The shear stress field lines on the model surface in the 0≤ α ≤35° angles of attack became visible by oil and pigments. Noteworthy and distinct aspect of the present study is the application of two empirical visualizing methods which made three dimensional vortical field more understandable. Formation and development of the primary and secondary vortex along the model length are qualitatively interpreted by the results of the smoke and laser light visualization technique. Moreover, the primary and secondary separation lines along model length for various angles of attack were deduced from the results of the oil flow visualization.