Effects of disturbed inflow on vortex shedding from a bluff body

Abstract

In the present chapter, the problem of accurate determination of mass flows by means of the so-called vortex-shedding flowmeter is studied for the case of disturbed inflow. To this end, the flow around bluff bodies of different designs, used in typical vortexshedding flow meters, was numerically simulated using a solver of the unsteady, compressible Navier-Stokes equations in three dimensions. The computations were carried out for several types of disturbed inflow conditions, including bends, flow with rotation oriented in the axial direction and unsteady flow fluctuations. The results were compared with experimental data obtained in an ongoing investigation. The effects of turbulence were modeled by using large-eddy simulation (LES). The resulting flow fields were analyzed using various methods, including visualization, evaluation of several of the features and DFT of properly chosen variables. Recommendations regarding the operational conditions of the vortex-shedding flow meters are made. © Springer-Verlag Berlin Heidelberg 2005.