Experimental Study on the Effect of Oscillation on Turbulent Air Flow through a Ninety Degree Bend

Turbulent air flow through a ninety degree bend under external low frequencies of 1.5 and 3 Hz was investigated experimentally by using Hot Wire Anemometer. The bend had a diameter of 106 mm and a curvature radius ratio of 6.0 with long, straight upstream and, downstream pipes. In the experimental study, The Measurements were performed for air flow rate with the bulk mean velocity of 10.97 m/s that corresponds to Reynolds number of 31200, for the standpoints of radial and axial velocity. In the Inlet plane of the bend due to the pressure gradient generated in the longitudinal direction of the bend, the Maximum velocity appeared toward the inner wall of the bend. The Maximum velocity was seen off-center at the inlet plane of the bend, showing the strong effect of bend downstream. At the outlet plane of the bend the velocity profile flattened due to extra mixing induced in the flow by oscillation.