A coupled finite-volume (FV)/finite-element (FE) numerical model of the straight-tube Coriolis flowmeter is considered. It uses the staggered partitioned algorithm with additional pressure predictor and interfield iterations to minimize the time lag in the fluid–structure coupling procedure. The solutions were evaluated in terms of the fundamental natural frequency of the vibrating system and the corresponding phase difference between the motion of the symmetrically located sensing points on the measuring tube, which are actually exploited as the measuring effects of the Coriolis flowmeter for the fluid density and the mass flowrate, respectively. The FV/FE numerical model was validated by comparison with the solutions of the Euler beam and one-dimensional flow model, as well as with the solutions of the Flügge shell and potential flow model. The respective simulations were performed for different lengths of the measuring tube.