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Research on Dispersion and Transport of Non-spherical Particles in Turbulent...
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Research on Dispersion and Transport of Non-spherical Particles in Turbulent Flows

A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Ocean Engineering".

Deadline for manuscript submissions: closed (25 November 2022) | Viewed by 9874

Special Issue Editor

Dr. Alessandro Capone

E-Mail Website
Guest Editor
Consiglio Nazionale delle Ricerche, Rome, Italy
Interests: multiphase flows; separated flows; wake flows; boundary layers; experimental methods for flow diagnostics

Special Issue Information

Dear Colleagues,

Transport and dispersion phenomena of non-spherical, anisotropic particles in turbulent flows are ubiquitous in industrial and natural processes, ranging from wastewater treatment to plankton transport in water bodies, micro-plastic pollution and sediment re-suspension. Within such multi-phase flows, and to an extent which depends on particle concentration, complex interactions between fluid phase and dispersed particles can take place with the onset of phenomena such as preferential particle transport and orientation and turbulence modulation effects. In particular, the dynamic coupling of turbulent motion to dispersed particle motion may lead to phenomena of particle concentration and accumulation. These events play a key role in critical subjects such as micro-plastic water pollution.

This Special Issue aims to provide an overview of the current research on non-spherical (solid, liquid or gaseous) particles transport, dispersion, orientation and deformation in turbulent flows. Contributions are encouraged on the following subjects:

  • Dynamics of non-spherical particles in free-shear flows
  • Dynamics of non-spherical particles in confined flows (channel, pipe flows)
  • Accumulation, orientation and deformation of non-spherical particles in turbulent flows
  • Turbulence modulation by non-spherical particles
  • Sediment resuspension
  • Experimental methods for research on non-spherical particles
We look forward to receiving your contributions.

Dr. Alessandro Capone
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Marine Science and Engineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Multiphase flows
  • Non-spherical particles
  • Preferential concentration
  • Turbulent transport
  • Micro-plastic dispersion and accumulation
  • Sediments resuspension
  • Bubble flows

Published Papers (4 papers)

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Research

14 pages, 3034 KiB  
Article
On the Turbulent Drag Reduction Effect of the Dynamic Free-Slip Surface Method
by Cong Wang and Morteza Gharib
J. Mar. Sci. Eng. 2022, 10(7), 879; https://doi.org/10.3390/jmse10070879 - 27 Jun 2022
Viewed by 1404
Abstract
The turbulent boundary layer (TBL) over the hull surface of a water vehicle significantly elevates the drag force on the water vehicle. In this regard, effectively controlling the TBL can lead to a drag reduction (DR) effect and therefore improve the energy efficiency [...] Read more.
The turbulent boundary layer (TBL) over the hull surface of a water vehicle significantly elevates the drag force on the water vehicle. In this regard, effectively controlling the TBL can lead to a drag reduction (DR) effect and therefore improve the energy efficiency of water transportation. Many DR methods have demonstrated promising DR effects but face challenges in implementation at the scale of engineering application. In this regard, the recently developed dynamic free-slip surface method can resolve some of the critical challenges. It employs an array of freely oscillating air–water interfaces to manipulate the TBL and can achieve a substantial DR effect under certain control conditions. However, the optimal setting of the control parameters that would maximize the DR effect remains unclear. To answer these questions, this study systematically investigates the effects of multiple control parameters for the first time, including the geometric size and curvature of the interface, the frequency of active oscillation, and the Reynolds number of TBL. Digital Particle Image Velocimetry was used to non-invasively measure the velocity and vorticity field of the TBL, and the Charted Clauser method was used to calculate the DR effect. The presented results suggest that the oscillating free-slip interfaces reduce the flow velocity near the wall boundary and lift the transverse vorticity (and the viscous shear stress) away from the wall. In addition, the shape factor of the TBL is elevated by the oscillating interfaces and slowly relaxes back in the downstream regions, which implies a partial relaminarization process induced in the TBL. Up to 36% DR effect was achieved within the current scope range of the control parameters. All of the results consistently suggest that a large DR effect is achieved when the free-slip interfaces oscillate with large Weber numbers. These discoveries shed light on the underlying DR mechanism and provide guidance for the future development of an effective drag control technique based on the dynamic free-slip surface method. Full article
(This article belongs to the Special Issue Research on Dispersion and Transport of Non-spherical Particles in Turbulent Flows)
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28 pages, 3298 KiB  
Article
A Model for Translation and Rotation Resistance Tensors for Superellipsoidal Particles in Stokes Flow
by Mitja Štrakl, Matjaž Hriberšek, Jana Wedel, Paul Steinmann and Jure Ravnik
J. Mar. Sci. Eng. 2022, 10(3), 369; https://doi.org/10.3390/jmse10030369 - 4 Mar 2022
Cited by 4 | Viewed by 2536
Abstract
In this paper, forces and torques on solid, non-spherical, orthotropic particles in Stokes flow are investigated by using a numerical approach on the basis of the Boundary Element Method. Different flow patterns around a particle are considered, taking into account the contributions of [...] Read more.
In this paper, forces and torques on solid, non-spherical, orthotropic particles in Stokes flow are investigated by using a numerical approach on the basis of the Boundary Element Method. Different flow patterns around a particle are considered, taking into account the contributions of uniform, rotational and shear flows, to the force and the torque exerted on the particle. The expressions for the force and the toque are proposed, by introducing translation, rotation and deformation resistance tensors, which capture each of the flow patterns individually. A parametric study is conducted, considering a wide range of non-spherical particles, determined by the parametric superellipsoid surface equation. Using the results of the parametric study, an approximation scheme is derived on the basis of a multivariate polynomial expression. A coefficient matrix for the polynomial model is introduced, which is used as a tunable parameter for a minimization problem, whereby the polynomials are fitted to the data. The developed model is then put to the test by considering a few examples of particles with different shapes, while also being compared to other, currently available solutions. On top of that, the full functionality of the model is demonstrated by considering an example of a pollen grain, as a realistic non-spherical particle. First, a superellipsoid, which best fits the actual particle shape, is found from the considered range. After that, the coefficients of the translation, rotation and deformation resistance tensors are obtained from the present model and compared to the results of other available models. In the conclusion, a superior accuracy of the present model, for the considered range of particles, is established. To the best of the authors knowledge, this is also one of the first models to extend the torque prediction capabilities beyond sphere and prolate particles. At the same time, the model was demonstrated to be simple to implement and very conservative with the computational resources. As such, it is suitable for large scale studies of dispersed two-phase flows, with a large number of particles. Full article
(This article belongs to the Special Issue Research on Dispersion and Transport of Non-spherical Particles in Turbulent Flows)
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12 pages, 2220 KiB  
Article
Microplastics in Combined Sewer Overflows: An Experimental Study
by Fabio Di Nunno, Francesco Granata, Francesco Parrino, Rudy Gargano and Giovanni de Marinis
J. Mar. Sci. Eng. 2021, 9(12), 1415; https://doi.org/10.3390/jmse9121415 - 11 Dec 2021
Cited by 11 | Viewed by 3084
Abstract
One of the main sources of microplastics inside surface waters is represented by combined sewer overflows (CSOs), involving severe risks for the environment. The entry of microplastics into water bodies also depends on the characteristics of sewer diversion structures used as flow control [...] Read more.
One of the main sources of microplastics inside surface waters is represented by combined sewer overflows (CSOs), involving severe risks for the environment. The entry of microplastics into water bodies also depends on the characteristics of sewer diversion structures used as flow control devices. In this work, an experimental investigation was carried out to evaluate the outflow of microplastic particles, consisting of different types of nylon fibers, from a side weir located on a channel with a rectangular section. A specific methodology was developed for the fiber sampling and outflow assessment after the tests were performed. For the tested configurations, an increase in fibers discharged up to 196.15% was measured as the water flow rate increased by 62.75%, combined with an increase in the side weir length up to 40% and a decrease in the crest height up to 20%. The size and weight of the different fibers showed a low impact due to their low inertia, and their motion was governed by the water flow. An empirical equation to evaluate the fiber outflow as a function of water flow rate and side weir geometric characteristics was also proposed and calibrated for the experimentally tested ranges of the dimensionless lateral water outflow Q* = 0.51–0.83 and of the dimensionless geometric parameter S* = 0.114–0.200. These first experimental results make it possible to carry out a preliminary assessment of the impact of CSOs in terms of microplastics spilled into water bodies. Full article
(This article belongs to the Special Issue Research on Dispersion and Transport of Non-spherical Particles in Turbulent Flows)
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17 pages, 5302 KiB  
Article
Flow-Particle Coupling in a Channel Flow Laden with Elongated Particles: The Role of Aspect Ratio
by Alessandro Capone, Fabio Di Felice and Francisco Alves Pereira
J. Mar. Sci. Eng. 2021, 9(12), 1388; https://doi.org/10.3390/jmse9121388 - 6 Dec 2021
Cited by 6 | Viewed by 2142
Abstract
A turbulent channel flow laden with elongated, fiber-like particles is investigated experimentally by optical techniques. The flow-particle inter-coupling is analyzed in the case of particles with an aspect ratio of 40 and 80, at two volume fractions, 10−5 and 10−4. [...] Read more.
A turbulent channel flow laden with elongated, fiber-like particles is investigated experimentally by optical techniques. The flow-particle inter-coupling is analyzed in the case of particles with an aspect ratio of 40 and 80, at two volume fractions, 10−5 and 10−4. An image processing technique is presented, which is employed to simultaneously obtain carrier flow velocimetry data and distribution and orientation data of dispersed particles. Turbulence enhancement is reported in the near-wall region, with a higher level of increase associated with higher aspect ratio particles. Comparison to fiber data suggests that this mechanism of turbulence modulation stems from a particles orientational behavior. The preferential particle distribution is reported to be dependent on the aspect ratio in the region close to the wall. The probability density function of the fibers’ orientation angle appears to be independent of the particle aspect ratio once it is conditioned to the fibers’ characteristic size. Full article
(This article belongs to the Special Issue Research on Dispersion and Transport of Non-spherical Particles in Turbulent Flows)
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