Investigation of numerical approaches to modeling large-scale turbulent vortex flows in the mode of vertical take-off and landing of an aircraft

Collective behaviors of motile units through hydrodynamic interactions induce directed fluid flow on a larger length scale than individual units. In cells, active cytoskeletal systems composed of polar filaments and molecular motors drive fluid flow, a process known as cytoplasmic streaming. The motor-driven elongation of microtubule bundles generates turbulent-like flow in purified systems; however, it remains unclear whether and how microtubule bundles induce large-scale directed flow like the cytoplasmic streaming observed in cells. Here, we adopted Xenopus egg extracts as a model system of the cytoplasm and found that microtubule bundle elongation induces directed flow for which the length scale and timescale depend on the existence of geometrical constraints. At the lower activity of dynein, kinesins bundle and slide microtubules, organizing extensile microtubule bundles. In bulk extracts, the extensile bundles connected with each other and formed a random network, and vortex flows with a length scale comparable to the bundle length continually emerged and persisted for 1 min at multiple places. When the extracts were encapsulated in droplets, the extensile bundles pushed the droplet boundary. This pushing force initiated symmetry breaking of the randomly oriented bundle network, leading to bundles aligning into a rotating vortex structure. This vortex induced rotational cytoplasmic flows on the length scale and timescale that were 10- to 100-fold longer than the vortex flows emerging in bulk extracts. Our results suggest that microtubule systems use not only hydrodynamic interactions but also mechanical interactions to induce large-scale temporally stable cytoplasmic flow.

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MODFLOW’s River Package: Part 2: Correction, Combining Analytical and Numerical Approaches

Physical Science International Journal ◽

10.9734/psij/2019/v22i330131 ◽

2019 ◽

pp. 1-23

Author(s):

Hubert J. Morel-Seytoux

Keyword(s):

Large Scale ◽

The Other ◽

Previous Article ◽

Regional Studies ◽

Hydrologic Models ◽

Numerical Efficiency ◽

Flow Interaction ◽

Numerical Approaches

Most widely used integrated hydrologic models still describe the flow interaction between streams and aquifers using primitive early concepts. In the previous article the shortcomings of the methodology were shown in great details. In this second part means are presented by which improvements can be introduced into the procedures. Accuracy and numerical efficiency will be improved. The article describes in details the proposed alternatives for both the saturated and the unsaturated connections. In the article reference is made specifically to the code MODFLOW. Most of the other integrated hydrologic models used for large-scale regional studies apply essentially the same methodology to estimate seepage.

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Distinctive features of the development of large-scale disturbances in vortex flows

Journal of Engineering Physics ◽

10.1007/bf00873714 ◽

1984 ◽

Vol 47 (3) ◽

pp. 1035-1038

Author(s):

V. A. Bobr ◽

L. I. Evdokimova ◽

V. I. Kalilets ◽

N. I. Pavlov ◽

A. A. Solov'ev ◽

...

Keyword(s):

Large Scale ◽

Vortex Flows ◽

Distinctive Features

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The modelling of power plant’s evaporative cooling tower operation taking into account hydrometeorological conditions

E3S Web of Conferences ◽

10.1051/e3sconf/201911600081 ◽

2019 ◽

Vol 116 ◽

pp. 00081

Author(s):

Alexander Solovyev ◽

Dmitriy Solovyev ◽

Liubov Shilova ◽

Aleksey Adamtsevich

Keyword(s):

Power Plants ◽

Large Scale ◽

Evaporative Cooling ◽

Practical Implementation ◽

Cooling Towers ◽

Turbulent Vortex ◽

Mathematical Algorithm ◽

Circulating Water ◽

Evaporative Cooling Tower ◽

Hydrometeorological Conditions

The paper aims to perform numerical modelling of the operation of large-scale evaporative cooling towers of power plants considering dynamically changing hydrometeorological conditions. The proposed modelling was performed based on the developed mathematical algorithm for studying the influence of turbulent vortex motions on the processes of atmospheric cooling of circulating water in countercurrent cooling towers of power plants. According to the simulation results, the optimal heat exchange modes of cooling towers operation are determined and recommendations for the practical implementation of measures to improve their thermal efficiency in hot periods of the year are proposed.

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The multiphase physics of sea ice: a review

The Cryosphere Discussions ◽

10.5194/tcd-5-1949-2011 ◽

2011 ◽

Vol 5 (4) ◽

pp. 1949-1993 ◽

Cited By ~ 2

Author(s):

E. C. Hunke ◽

D. Notz ◽

A. K. Turner ◽

M. Vancoppenolle

Keyword(s):

Sea Ice ◽

Large Scale ◽

Climate Modeling ◽

Liquid Solution ◽

Earth System ◽

Ice Crystal ◽

Water Ice ◽

Multiphase Materials ◽

Research Initiatives ◽

Numerical Approaches

Abstract. Rather than being solid throughout, sea ice contains liquid brine inclusions, solid salts, microalgae, trace elements, gases, and other impurities which all exist in the interstices of a porous, solid ice matrix. This multiphase structure of sea ice arises from the fact that the salt that exists in seawater cannot be embedded into the water-ice crystal lattice upon formation of sea ice, but remains in liquid solution. Depending on the ice porosity (determined by temperature and salinity), this brine can drain from the ice, taking other sea ice constituents with it. Thus, sea ice salinity and microstructure are tightly interconnected and play a significant role in polar ecosystems and climate. As large-scale climate modeling efforts move toward "earth system" simulations that include biological and chemical cycles, renewed interest in the multiphase physics of sea ice has strengthened research initiatives to observe, understand and model this complex system. This review article provides an overview of these efforts, highlighting known difficulties and requisite observations for further progress in the field. We focus on mushy-layer theory, which describes general multiphase materials, and on numerical approaches now being explored to model the multiphase evolution of sea ice and its interaction with chemical, biological and climate systems.

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Diagnosis of Pre-Depression Large-Scale Vortex Instability in the Tropical Atmosphere

10.5194/egusphere-egu21-6966 ◽

2021 ◽

Author(s):

Galina Levina

Keyword(s):

Mirror Symmetry ◽

Large Scale ◽

Tropical Cyclogenesis ◽

Theoretical Ground ◽

Tropical Atmosphere ◽

Vortex Instability ◽

Turbulent Vortex ◽

Convective Clouds ◽

Vortical Hot Towers ◽

Large Scale Vortex

An approach is proposed [1] for determining the precise time of the start of tropical cyclogenesis, which includes a combined analysis of data from cloud-resolving numerical modeling and GOES Imagery. The approach is based on the similarity of patterns in the fields of vertical helicity (numerical simulation) and temperature (satellite data), allowing for the localization of intense rotating convective clouds known as the Vortical Hot Towers. As a theoretical ground, we applied a hypothesized (to date) interpretation of tropical cyclogenesis as a large-scale instability caused by the mechanism of the turbulent vortex dynamo in the atmosphere [1,2], and with bearing in mind the crucial role of Vortical Hot Towers in providing the dynamo-effect [2]. In this context, birth of a hurricane is considered as an extreme threshold event in the helical atmospheric turbulence of a vorticity-rich environment of a pre-depression cyclonic recirculation zone. Helical turbulence is characterized by the broken mirror symmetry and permits an existence of inverse energy cascade in three-dimensional cases. In order to trace and analyze processes of self-organization in the tropical atmosphere, that span scales from convective clouds with horizontal dimensions of 1-5 km to mesoscale vortices of hundreds of kilometers, we used the post-processing [1-3] of data from cloud-resolving numerical simulations [4].&#160; Implementation of the proposed approach revealed that large-scale vortex instability can begin a few hours, or even dozens of hours, before the formation of the Tropical Depression. This work was supported by the research project &#8220;Monitoring&#8221; No. 01200200164.References[1] Levina, G. V., 2020. Birth of a hurricane: early detection of large-scale vortex instability. J. Phys.: Conf. Ser., 1640&#160; 012023, &#160;doi:10.1088/1742-6596/1640/1/012023[2] Levina, G. V., 2018. On the path from the turbulent vortex dynamo theory to diagnosis of tropical cyclogenesis. Open J. Fluid Dyn., 8, 86&#8211;114, &#160;https://doi.org/10.4236/ojfd.2018.81008[3] Levina, G. V. and M. T. Montgomery, 2015. When will Cyclogenesis Commence Given a Favorable Tropical Environment? &#160;Procedia IUTAM, 17, 59&#8211;68, https://doi.org/10.1016/j.piutam.2015.06.010[4] Montgomery, M. T., M. E.&#160; Nicholls, T. A. Cram, and A. B. Saunders, 2006: A vortical hot tower route to tropical cyclogenesis. J. Atmos. Sci., 63, 355&#8211;386, &#160;https://doi.org/10.1175/JAS3604.1

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The multiphase physics of sea ice: a review for model developers

The Cryosphere ◽

10.5194/tc-5-989-2011 ◽

2011 ◽

Vol 5 (4) ◽

pp. 989-1009 ◽

Cited By ~ 69

Author(s):

E. C. Hunke ◽

D. Notz ◽

A. K. Turner ◽

M. Vancoppenolle

Keyword(s):

Sea Ice ◽

Large Scale ◽

Climate Modeling ◽

Liquid Solution ◽

Review Article ◽

Gas Content ◽

Earth System ◽

Multiphase Materials ◽

Research Initiatives ◽

Numerical Approaches

Abstract. Rather than being solid throughout, sea ice contains liquid brine inclusions, solid salts, microalgae, trace elements, gases, and other impurities which all exist in the interstices of a porous, solid ice matrix. This multiphase structure of sea ice arises from the fact that the salt that exists in seawater cannot be incorporated into lattice sites in the pure ice component of sea ice, but remains in liquid solution. Depending on the ice permeability (determined by temperature, salinity and gas content), this brine can drain from the ice, taking other sea ice constituents with it. Thus, sea ice salinity and microstructure are tightly interconnected and play a significant role in polar ecosystems and climate. As large-scale climate modeling efforts move toward "earth system" simulations that include biological and chemical cycles, renewed interest in the multiphase physics of sea ice has strengthened research initiatives to observe, understand and model this complex system. This review article provides an overview of these efforts, highlighting known difficulties and requisite observations for further progress in the field. We focus on mushy layer theory, which describes general multiphase materials, and on numerical approaches now being explored to model the multiphase evolution of sea ice and its interaction with chemical, biological and climate systems.

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Experimental and numerical investigation of mode II failure behavior evaluation using three point bend, end notched flexure test

MATEC Web of Conferences ◽

10.1051/matecconf/201814402009 ◽

2018 ◽

Vol 144 ◽

pp. 02009 ◽

Cited By ~ 1

Author(s):

R. Nikhil ◽

S. Shivakumar ◽

Kallol Anupama ◽

Shettar Manjunath

Keyword(s):

Crack Propagation ◽

Large Scale ◽

Fiber Reinforced Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Displacement Response ◽

Load Displacement ◽

Crack Paths ◽

Bridged Crack ◽

Numerical Approaches

In the present paper the primary task is the study involving calculation of elastic properties of the composite from the individual properties of the E-glass fiber (650 GSM) and the properties of resin LY 556 with Hardener HY951. The properties of varying volumetric ratio of fiber are obtained from calculation of the properties by using rule of mixtures. Experimentally validating the theoretical and numerical approaches by comparing the load-displacement response and crack paths observed in large scale bridged crack propagation in laminated fiber-reinforced composites specimens. An effort is being made to develop a numerical framework for cohesive crack propagation and demonstrating its effectiveness by simulating failure through crack propagation in materials with complex microstructure like fiber reinforced composites. Experimentally validating the theoretical and numerical approaches by comparing the load-displacement response and crack paths observed in large scale bridged crack propagation in laminated fiber-reinforced composites specimens.

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Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

International Astronomical Union Colloquium ◽

10.1017/s0252921100031493 ◽

1999 ◽

Vol 173 ◽

pp. 243-248

Author(s):

D. Kubáček ◽

A. Galád ◽

A. Pravda

Keyword(s):

Image Processing ◽

Large Scale ◽

Harvard College ◽

Oak Ridge ◽

Large Scale Structures ◽

Short Period Comet ◽

Short Period ◽

Scale Structures ◽

Harvard College Observatory ◽

Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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Evolution of Large-Scale Coronal Structures

International Astronomical Union Colloquium ◽

10.1017/s0252921100024945 ◽

1994 ◽

Vol 144 ◽

pp. 29-33

Author(s):

P. Ambrož

Keyword(s):

Magnetic Field ◽

Field Line ◽

Large Scale ◽

Coronal Magnetic Field ◽

Source Surface ◽

Solar Cycles ◽

Characteristic Relationship ◽

The Magnetic Field ◽

Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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