Torsional waves propagation along a waveguide of arbitrary cross section immersed in a perfect fluid

Abstract

Guided torsional waves in a bar with a noncircular cross section have been exploited by previous researchers to measure the density of fluids. However, due to the complexity of the wave behavior in the noncircular cross-sectional shape, the previous theory can only provide an approximate prediction; thus the accuracy of the measurement has been compromised. In this paper, a semianalytical finite element method is developed to model accurately the propagation velocity and leakage of guided waves along an immersed waveguide with arbitrary noncircular cross section. An accurate inverse model is then provided to measure the density of the fluid by measuring the change of the torsional wave speed. Experimental results obtained with a rectangular bar in a range of fluids show very good agreement with the theoretical predictions. Finally, the potentials to use the model for sensor optimization are discussed.

Understanding acoustic physics in oil and gas wellbores with the presence of ubiquitous geometric eccentricity

“…To understand the acoustic guided wave propagation characteristics in embedded cylindrical structures is of significance in many fields such as ultrasonic Nondestructive Evaluation (NDE) [1][2] , civil engineering 3 , and geotechnical engineering [4][5][6] . Ultrasonic guided waves are routinely used for pipework inspections in a variety of industries such as oil and gas, power and nuclear plants, and petrochemical industries.…”

“…Ultrasonic guided waves are routinely used for pipework inspections in a variety of industries such as oil and gas, power and nuclear plants, and petrochemical industries. The technology offers the possibility of rapid screening over long lengths of pipes for the detection of corrosions and other damages 1,2 . The fact that most pipelines are buried underground and/or coated with protective layers presents challenges for the coupled waveguides as energy could leak into the surrounding media 1 .…”

Guided wave propagation in metallic and resin plates loaded with water on single surface

“…Semi-analytical finite element (SAFE) calculations have been developed as an efficient calculation technique for guided waves propagating in elongated structures such as plates and pipes [3][4][5][6][7][8][9]. Most of the SAFE calculations were formulated for guided waves in an elastic waveguide with homogeneous geometry and material constants in the longitudinal direction under the traction-free boundary conditions.…”

Guided waves' dispersion curves in anisotropic viscoelastic single- and multi-layered media

“…The number of degree of freedom in our models is less than 11 000, and the typical calculation time for each SAFE model on a standard PC (Intel Core i7, 8 GB memory) was less than 15 s. The convergence has been checked in the models used in our paper, and the results are satisfactory. In fact, this implementation of the SAFE model has already been validated in multi-layer structures [54] as well as solid-fluid structures [55] in which there is a strong impedance contrast. For chosen values of angular frequency ω, eigenvalues of complex wavenumber k are found, in which the real part describes the harmonic wave propagation while its imaginary part presents the attenuation.…”