Flow Resistance of a Vortex Shedder in a Circular Pipe

Concerning the Karman vortex flowmeter, an experimental investigation was performed on the resistance of a vortex shedder in a turbulent flow through a circular pipe. The shedders are cylindrical bodies having various cross sections. The open ratio β ranged from 0.660 to 0.915 and the Reynolds number based on the diameter of the pipe and the mean velocity of the flow ranged from 1.9×104 to 2.47×105. The resistance coefficient K is given as follows regardless of the Reynolds number : K=C(1-β)/β2. The constant C is proportional to the drag coefficient, CD, of the shedder in a uniform flow, that is, C=0.8 CD.