scholarly journals Three-dimensional magma flow dynamics within subvolcanic sheet intrusions

Geosphere ◽  
2016 ◽  
Vol 12 (3) ◽  
pp. 842-866 ◽  
Author(s):  
C. Magee ◽  
B. O’Driscoll ◽  
M.S. Petronis ◽  
C.T.E. Stevenson
Keyword(s):  
Three Dimensional ◽  
Flow Dynamics ◽  
Magma Flow

Flow dynamics and enhanced mixing in a converging–diverging channel

2016 ◽  
Vol 807 ◽  
pp. 167-204 ◽  
Author(s):  
S. W. Gepner ◽  
J. M. Floryan
Keyword(s):  
Three Dimensional ◽  
Travelling Wave ◽  
Flow Dynamics ◽  
Streamwise Vortices ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Wave Instability ◽  
Unsteady Separation ◽  
Flow Stabilization ◽  
Diverging Channel

An analysis of flows in converging–diverging channels has been carried out with the primary goal of identifying geometries which result in increased mixing. The model geometry consists of a channel whose walls are fitted with spanwise grooves of moderate amplitudes (up to 10 % of the mean channel opening) and of sinusoidal shape. The groove systems on each wall are shifted by half of a wavelength with respect to each other, resulting in the formation of a converging–diverging conduit. The analysis is carried out up to Reynolds numbers resulting in the formation of secondary states. The first part of the analysis is based on a two-dimensional model and demonstrates that increasing the corrugation wavelength results in the appearance of an unsteady separation whose onset correlates with the onset of the travelling wave instability. The second part of the analysis is based on a three-dimensional model and demonstrates that the flow dynamics is dominated by the centrifugal instability over a large range of geometric parameters, resulting in the formation of streamwise vortices. It is shown that the onset of the vortices may lead to the elimination of the unsteady separation. The critical Reynolds number for the vortex onset initially decreases as the corrugation amplitude increases but an excessive increase leads to the stream lift up, reduction of the centrifugal forces and flow stabilization. The flow dynamics under such conditions is again dominated by the travelling wave instability. Conditions leading to the formation of streamwise vortices without interference from the travelling wave instability have been identified. The structure and the mixing properties of the saturated states are discussed.

scholarly journals Quantifying blood flow dynamics during cardiac development: demystifying computational methods

2018 ◽  
Vol 373 (1759) ◽  
pp. 20170330 ◽  
Author(s):  
Katherine Courchaine ◽  
Sandra Rugonyi
Keyword(s):  
Blood Flow ◽  
Congenital Heart ◽  
Cardiac Development ◽  
Three Dimensional ◽  
Flow Dynamics ◽  
Cardiovascular Development ◽  
Flow Conditions ◽  
Congenital Heart Malformations ◽  
Blood Flow Dynamics ◽  
Altered Blood

Blood flow conditions (haemodynamics) are crucial for proper cardiovascular development. Indeed, blood flow induces biomechanical adaptations and mechanotransduction signalling that influence cardiovascular growth and development during embryonic stages and beyond. Altered blood flow conditions are a hallmark of congenital heart disease, and disrupted blood flow at early embryonic stages is known to lead to congenital heart malformations. In spite of this, many of the mechanisms by which blood flow mechanics affect cardiovascular development remain unknown. This is due in part to the challenges involved in quantifying blood flow dynamics and the forces exerted by blood flow on developing cardiovascular tissues. Recent technologies, however, have allowed precise measurement of blood flow parameters and cardiovascular geometry even at early embryonic stages. Combined with computational fluid dynamics techniques, it is possible to quantify haemodynamic parameters and their changes over development, which is a crucial step in the quest for understanding the role of mechanical cues on heart and vascular formation. This study summarizes some fundamental aspects of modelling blood flow dynamics, with a focus on three-dimensional modelling techniques, and discusses relevant studies that are revealing the details of blood flow and their influence on cardiovascular development. This article is part of the Theo Murphy meeting issue ‘Mechanics of development’.

Three-Dimensional Hybrid Vortex-Immersed Boundary Method With Application to Passive Flow Control

2015 ◽  
Author(s):  
Chloé Mimeau ◽  
Iraj Mortazavi ◽  
Georges-Henri Cottet
Keyword(s):  
Immersed Boundary Method ◽  
Incompressible Flows ◽  
Three Dimensional ◽  
Flow Dynamics ◽  
Immersed Boundary ◽  
Bluff Bodies ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Model Complex ◽  
Penalization Technique

In this work, a hybrid particle-penalization technique is proposed to achieve accurate and efficient computations of 3D incompressible flows past bluff bodies. This immersed boundary approach indeed maintains the efficiency and the robustness of vortex methods and allows to easily model complex media, like solid-fluid-porous ones, without prescribing any boundary condition. In this paper, the method is applied to implement porous coatings on a hemisphere in order to passively control the flow dynamics.

A three‐dimensional numerical model investigation of the impact of submerged macrophytes on flow dynamics in a large fluvial lake

2019 ◽  
Vol 64 (9) ◽  
pp. 1627-1642 ◽  
Author(s):  
Maxim Bulat ◽  
Pascale M. Biron ◽  
Jay R. W. Lacey ◽  
Morgan Botrel ◽  
Christiane Hudon ◽  
...  
Keyword(s):  
Numerical Model ◽  
Submerged Macrophytes ◽  
Three Dimensional ◽  
Flow Dynamics ◽  
Model Investigation ◽  
Fluvial Lake ◽  
The Impact

A Lattice Boltzmann Simulation of Three-Dimensional Displacement Flow of Two Immiscible Liquids in a Square Duct

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Prasanna R. Redapangu ◽  
Kirti Chandra Sahu ◽  
S. P. Vanka
Keyword(s):  
Lattice Model ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Flow Dynamics ◽  
Two Dimensional ◽  
Immiscible Liquids ◽  
Square Duct ◽  
Lattice Boltzmann Simulation ◽  
Pressure Driven

A three-dimensional (3D), multiphase lattice Boltzmann approach is used to study a pressure-driven displacement flow of two immiscible liquids of different densities and viscosities in a square duct. A three-dimensional, 15-velocity (D3Q15) lattice model is used. The effects of channel inclination, viscosity, and density contrasts are investigated. The contours of the density and the average viscosity profiles in different planes are plotted and compared with those obtained in a two-dimensional (2D) channel. We demonstrate that the flow dynamics in a 3D channel is quite different as compared to that of a 2D channel. We found that the flow is relatively more coherent in a 3D channel than that in a 2D channel. A new screw-type instability is seen in the 3D channel that cannot be observed in the 2D channel.

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