Experimental measurements in the turbulent wake behind tandem open base cones with four different apex angles of 30, 45, 60 and 90 degrees and the separation distance between the cones fixed at 1.5 cone base diameter (1.5 D) at a Reynolds number of 4x104 were undertaken. Measurements in the wake of single cones at the same Reynolds number have also been performed for comparison. The measurements were extended up to a down stream distance of 10 diameters behind the second cone. All measurements were performed using hot wire anemometer with X-wire probe.
Mean velocity, turbulent intensity and shear stress show that the cone angle has an important effect on the wake development, drag force and mixing of the fluid in the near wake behind tandem cones. The measured drag coefficient increases with cone angle. The drag coefficient of tandem cones is lower than that of single open base cone of the same cone angle and Reynolds number. This is in accordance with the observed attenuation of turbulence in the wake of tandem cones.