Small-diameter ultrasonic flow meters present an interesting industrial internal-flow problem due to their unique geometry and complex interaction with fluid flow. In order to efficiently evaluate and optimise these flow meters, their flow physics must be accurately understood and predicted. In this study, computational fluid dynamics is used to predict the turbulent flow inside a residential ultrasonic flow meter with an intrusive two-stand configuration. Reynolds-averaged Navier–Stokes (RANS), with k−ɛ and k−ω SST turbulence models, are evaluated in a wall-modelled and a wall-resolved grid. The simulation results are compared against laser Doppler velocimetry, pressure drop, and vortices visualisation experiments in both qualitative and quantitative manners. Numerical results qualitatively agree with experimental data although some discrepancies are predicted by the k−ɛ model. Overall, the results that best predict the flow structures, axial velocity, and pressure drop are achieved by wall-resolved RANS k−ω SST model. While minor differences are predicted by the wall-modelled k−ω SST, it is concluded that this approach is a good candidate to perform time-efficient studies due to the reduced computational cost.
