On turbulence measurement in rotating magnetic field-driven flow

In this paper, we propose a new simplified lattice Boltzmann method (SLBM) for magnetohydrodynamic flows that outperforms the classical one in terms of accuracy, while preserving its advantages. A very recent paper [A. De Rosis, J. Al-Adham, H. Al-Ali and R. Meng, "Double-D2Q9 lattice Boltzmann models with extended equilibrium for two-dimensional magnetohydrodynamic flows", Phys. Fluids 33, 035143 (2021)] demonstrated that the SLBM enforces the divergence-free condition of the magnetic fiield in an excellent manner and involves the lowest amount of virtual memory. However, the SLBM is characterised by the poorest accuracy. Here, the two-stages algorithm that is typical of the SLBM is replaced by a one-stage procedure following the approach devised for non-conductive fluids in a very recent effort [A. Delgado-Gutierrez, P. Marzocca, D. Cardenas, and O. Probst, "A single-step and simplified graphics processing unit lattice Boltzmann method for high turbulent flows", International Journal for Numerical Methods in Fluids ( 2021)]. The Chapman-Enskog expansion formally demonstrates the consistency of the present scheme. The resultant algorithm is very compact and easy to be implemented. Given all these features, we believe that the proposed approach is an excellent candidate to perform numerical simulations of two-and three-dimensional magnetohydrodynamic flows.

Section: Discussionmentioning

confidence: 99%

One-stage simplified lattice Boltzmann method for two- and three-dimensional magnetohydrodynamic flows

Rosis

Revell

2021

Rotating magnetic dipole-driven flows in a conducting liquid cylinder

Grants

2021

Four configurations of a rotating magnetic dipole-driven turbulent flow in an electrically conducting liquid cylinder are considered by spectral direct numerical simulation. These configurations differ by parallel or perpendicular orientation of the dipole rotation vector with respect to the nearest surface of the cylinder or its axis. The rotating dipole generates electromagnetic force in a thin outer liquid layer facing it. A concentrated vortex is driven when the dipole rotation vector is perpendicular to the nearest surface. This vortex closely resembles the rotating disk-driven flow. When the dipole rotation vector is parallel to the nearest surface, then a distributed vortex occurs akin of the translating wall-driven cavity flow. The characteristic velocity is comparably little influenced by dipole orientation despite the electromagnetic force magnitude varying by a factor of three. Perpendicular orientation of the magnetic dipole rotation vector with respect to the cylinder's axis causes secondary corner eddies increasing the overall turbulent fluctuation. The simulations are supplemented by an experiment featuring a deep and narrow funnel-shaped quasi-stationary free surface deformation above a concentrated vortex.

Volume flow rate calculation model of non-full pipe multiphase flow based on ultrasonic sensors

Liang

Song

et al. 2023

In the oil and gas industry, it is crucial to employ appropriate drilling fluids to maintain equilibrium of formation pressure throughout the various stages of drilling operations. During the recycling process, the drilling fluid may precipitate gas and as a result, exhibit non-full pipe flow upon return to the surface. Accurate measurement of the volume flow rate of it is imperative in obtaining valuable information from the bottom of the well. Commonly, on-site drilling operations use a multiphase target flowmeter in conjunction with an empirical model to rectify calculation results. Therefore, the theoretical potential of utilizing non-contact ultrasonic sensors for measuring multiphase volume flow rate of non-full pipe flow is significant. In this research, an apparent flow velocity calculation model was established by integrating the ultrasonic Doppler shift model and pipeline fluid mechanics utilizing a four-channel ultrasonic array. Subsequently, the invariant scattering convolution -long short-term memory network was trained on the data-fused ultrasonic signal to identify the liquid level. The velocity-area method was also employed to establish a new multiphase volume flow calculation model. To evaluate the validity of the proposed model, comparison experiments of liquid single-phase flow and liquid-solid two-phase flow were conducted. The experimental results show that, compared with the comparative flow measurement system (CFMS), the accuracy of the ultrasonic flow measurement system (UFMS) is reduced by 0.965%, the nonlinear error (NLE) by 2.293 %, the average relative error (ARE) by 2.570 %, the standard deviation (SD) by 1.395, and the root mean square error (RMSE) by 14.394.