Variationally derived interface stabilization for discrete multiphase flows and relation with the ghost-penalty method

Zhu, Lixing; Masud, Arif

doi:10.1016/j.cma.2020.113404

Cited by 11 publications

(5 citation statements)

References 43 publications

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“…Investigations on other types of FOWT motion are underway, which will be presented in future work. These interactions between the wind, the FOWT and the waves, which can be solved using fully coupled two-phase CFD solvers (Li et al 2019;Zhu, Goraya & Masud 2019;Gatin et al 2020;Zhu & Masud 2021), are not considered, and will also be studied in a systematic way in future work. actuator surface model .…”

Section: Discussionmentioning

confidence: 99%

Onset of wake meandering for a floating offshore wind turbine under side-to-side motion

Dong

Yang

2022

J. Fluid Mech.

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Wind turbine wakes, being convectively unstable, may behave as an amplifier of upstream perturbations and make downstream turbines experience strong inflow fluctuations. In this work, we investigate the effects of the side-to-side motion of a floating offshore wind turbine (FOWT) on wake dynamics using large-eddy simulation and linear stability analysis (LSA). When the inflow turbulence intensity is low, simulation results reveal that the turbine motion with certain Strouhal numbers $St = fD/U_\infty \in (0.2,0.6)$ (where $f$ is the motion frequency, $D$ is the rotor diameter, and $U_\infty$ is the incoming wind speed), which overlap with the Strouhal numbers of wake meandering induced by the shear layer instability, can lead to wake meandering with amplitudes being one order of magnitude larger than the FOWT motion for the most unstable frequency. For high inflow turbulence intensity, on the other hand, the onset of wake meandering is dominated by the inflow turbulence. The probability density function of the spanwise instantaneous wake centres is observed being non-Gaussian and closely related to that of the side-to-side motion. This complements the existing wake meandering mechanisms, that the side-to-side motion of an FOWT can be a novel origin for the onset of wake meandering. It is also found that LSA can predict the least stable frequencies and the amplification factor with acceptable accuracy for motion amplitude $0.01D$ . Effects of nonlinearity are observed when motion amplitude increases to $0.04D$ , for which the most unstable turbine oscillations shift slightly to lower frequencies and the amplification factor decreases.

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Section: Discussionmentioning

confidence: 99%

Onset of wake meandering for a floating offshore wind turbine under side-to-side motion

Dong

Yang

2022

J. Fluid Mech.

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“…The VMS framework when viewed from the perspective of subgrade-scale physics provides a platform for variational coupling of multiple PDEs on concurrent and/or adjoining subdomains. Embedding ideas from the discontinuous Galerkin (DG) method in the bubble-enriched VMS framework, Masud and co-workers presented the variational multiscale discontinuous Galerkin (VMDG) methods (Masud et al, 2012;Truster and Masud, 2014;Zhu and Masud, 2021) with rigorous treatment of the continuity conditions that are critical to numerical and algorithmic stability. The VMDG method facilitates variational embedding of the fine-scale interface models in a mathematically consistent fashion, admits common element types, and is free of user-defined tuning parameters (Calderer and Masud, 2013;Chen et al, 2020;Masud and Truster, 2013;Truster and Masud, 2014;Zhu and Masud, 2021).…”

Section: Stabilized and Variational Multiscale Methods For Multiphysicsmentioning

confidence: 99%

“…Embedding ideas from the discontinuous Galerkin (DG) method in the bubble-enriched VMS framework, Masud and co-workers presented the variational multiscale discontinuous Galerkin (VMDG) methods (Masud et al, 2012;Truster and Masud, 2014;Zhu and Masud, 2021) with rigorous treatment of the continuity conditions that are critical to numerical and algorithmic stability. The VMDG method facilitates variational embedding of the fine-scale interface models in a mathematically consistent fashion, admits common element types, and is free of user-defined tuning parameters (Calderer and Masud, 2013;Chen et al, 2020;Masud and Truster, 2013;Truster and Masud, 2014;Zhu and Masud, 2021). The enhanced stability of the VMDG framework enables the treatment of various interface kinematics, such as nonmatching mashes in domain decomposition or substructure modeling, contact and friction in mechanical systems, and delamination at bimaterial interfaces in composites (Fig.…”

Section: Stabilized and Variational Multiscale Methods For Multiphysicsmentioning

confidence: 99%

A Multiscale Vision-Illustrative Applications From Biology to Engineering

Schlick

Portillo‐Ledesma

Blaszczyk³

et al. 2021

Int J Mult Comp Eng

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Modeling and simulation have quickly become equivalent pillars of research along with traditional theory and experimentation. The growing realization that most complex phenomena of interest span many orders of spatial and temporal scales has led to an exponential rise in the development and application of multiscale modeling and simulation over the past two decades. In this perspective, the associate editors of the International Journal for Multiscale Computational Engineering and their co-workers illustrate current applications in their respective fields spanning biomolecular structure and dynamics, civil engineering and materials science, computational mechanics, aerospace and mechanical engineering, and more. Such applications are highly tailored, exploit the latest and ever-evolving advances in both computer hardware and software, and contribute significantly to science, technology, and medical challenges in the 21st century.

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“…The signed distance function is used to represent the fluid-structure interface [23,37,38] and calculate n and G(l,t) in Eq. ( 5).…”

Section: Interface Representationmentioning

confidence: 99%

Control of a sedimenting elliptical particle by electromagnetic forces

Qin,

Dong,

Zhang

2021

Preprint

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In this paper, the effectiveness of electromagnetic forces on controlling the motion of a sedimenting elliptical particle is investigated using the immersed interface-lattice Boltzmann method (II-LBM), in which a signed distance function is adopted to apply the jump conditions for the II-LBM and to add external electromagnetic forces. First, mechanisms of electromagnetic control on suppressing vorticity generation based on the vorticity equation and vortex shedding based on the streamwise momentum equation are discussed. Then, systematical investigations are performed to quantify and qualify the effects of the electromagnetic control by changing the electromagnetic strength, the initial orientation angle of the elliptical particle, and the density ratio of the particle to the fluid. To demonstrate the control effect of different cases, comparisons of vorticity fields, particle trajectories, orientation angles, and energy transfers of the particles are presented. Results show that the rotational motion of the particle can be well controlled by appropriate magnitudes of electromagnetic forces. In a relatively high solid to fluid density ratio case where vortex shedding appears, the sedimentation speed can increase nearly 40% and the motion of the particle turns into a steady descent motion once an appropriate magnitude of the electromagnetic force is applied. When the magnitude of the electromagnetic force is excessive, the particle will deviate from the center of the side walls. In addition, the controlling approach is shown to be robust for various initial orientation angles and solid to fluid density ratios.

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Variationally derived interface stabilization for discrete multiphase flows and relation with the ghost-penalty method

Cited by 11 publications

References 43 publications

Onset of wake meandering for a floating offshore wind turbine under side-to-side motion

Onset of wake meandering for a floating offshore wind turbine under side-to-side motion

A Multiscale Vision-Illustrative Applications From Biology to Engineering

Control of a sedimenting elliptical particle by electromagnetic forces

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