In this study, changes in velocity, turbulence intensity and drag coefficient in the wake of a notch-back car modelling steady and unsteady flow is measured and evaluated. The blow open circuit wind tunnel is used to simulate fluid flow. Turbulence intensity and nominal maximum speed of the device is measured to be 0.01% and 30m/s, respectively. The speed has been continuously increased by an invertercausing changes in rotational speed of the electromotor. In the near location to the model, the results showed three different regimes in the velocity profile of the model’s wake. With increasing distance from the model and with increasing the speed, three regimes in the wake are close to each other. Drag coefficient for several velocities is measured, where the result shows that decreasing in drag coefficient is proportional with increasing velocity. In addition, the changing trends of higher order velocity of parameters like flatness and skewedness are depicted. پرونده مقاله

In this paper, considering the importance of incoming flow turbulence intensity into combustion chamber, tripping wire effect on the flow wake has been experimentally investigated within a linear compressor cascade. To do this, two wires were implemented along each blade and their effects on average velocity, turbulence intensity and vortices frequencies at Reynolds number 45500 were accurately considered. To measure wake parameters, one–dimensional hot wire anemometer was used. It is found that turbulence promoters increased the maximum turbulence intensity in blades wake and also reduced corresponding frequency in maximum amplitude and the Strouhal number, consequently. پرونده مقاله

An experimental study was carried out on the wake of a cylinder on the back of which a plate is installed parallel to the fluid flow, with different terminal angles, where the Reynolds number is 50000. At the end of the plate, blades with the height of 0.25 equal to the cylinder diameter and with 45, 90 and 135 degrees angle from the horizon, are installed where the cylinder diameter is equal to the plate length. The plate effects on the variation of drag coefficient, medium velocity profiles, reduced velocity, half of the entrance, turbulence intensity and Strouhal number are investigated. The results showed that the drag coefficient for cylinder including the plate, regardless of the end angle, is smaller than the isolated cylinder. The existence of a plate with a terminal angle of 45 degree led to more reduction in drag coefficient of the cylinder. پرونده مقاله