A computational Study of Defects Dynamics of a 3-Dimensional Quenched Complex Field

1989 ◽  
Vol 58 (2) ◽  
pp. 563-570 ◽  
Author(s):  
Hiraku Nishimori ◽  
Tomohiro Nukii
Keyword(s):  
Computational Study ◽  
Complex Field ◽  
3 Dimensional

Computational Study of a Subsonic Aircraft Design: Basic CFD Methods and CAD Designs

2008 ◽  
Author(s):  
Scott Winkelmann ◽  
Ryoichi S. Amano
Keyword(s):  
Computational Study ◽  
Aircraft Design ◽  
Tetrahedral Mesh ◽  
Hexahedral Mesh ◽  
3 Dimensional ◽  
Dimensional Modeling ◽  
Basic Understanding ◽  
Modeling Software ◽  
Simple Features ◽  
Meshing Process

This investigation explores the methodology, using various computational tools and processes, involved in designing the fuselage of an aircraft. The design begins using 3-Dimensional modeling software and a basic understanding of aerodynamics. The form of the aircraft is built using only a few simple features and is then ready for the meshing process. Picking a simple tetrahedral mesh, rather than a more complicated hexahedral mesh, will allow this process to proceed even faster and also requires only a basic understanding of meshing. Once the geometry is completed the mesh may be moved into Computational Fluid Dynamics software and a wind tunnel simulation can be preformed. Developing a connection between each of these steps will allow the design to be manipulated in many different ways.

scholarly journals A Computational Study of Hydrodynamic Interactions Between Pairs of Sperm With Planar and Quasi-Planar Beat Forms

2021 ◽  
Vol 9 ◽  
Author(s):  
Lucia Carichino ◽  
Derek Drumm ◽  
Sarah D. Olson
Keyword(s):  
Minimum Distance ◽  
Computational Study ◽  
Hydrodynamic Interactions ◽  
Key Factors ◽  
Confined Geometries ◽  
Image System ◽  
3 Dimensional ◽  
Structure Interaction ◽  
Mammalian Sperm ◽  
Constant Distance

Although hydrodynamic interactions and cooperative swimming of mammalian sperm are observed, the key factors that lead to attraction or repulsion in different confined geometries are not well understood. In this study, we simulate the 3-dimensional fluid-structure interaction of pairs of swimmers utilizing the Method of Regularized Stokeslets, accounting for a nearby wall via a regularized image system. To investigate emergent trajectories of swimmers, we look at different preferred beat forms, planar or quasi-planar (helical with unequal radii). We also explored different initializations of swimmers in either the same plane (co-planar) or with centerlines in parallel planes. In free space, swimmers with quasi-planar beat forms and those with planar beat forms that are co-planar exhibit stable attraction. The swimmers reach a maintained minimum distance apart that is smaller than their initial distance apart. In contrast, for swimmers initialized in parallel beat planes with a planar beat form, we observe alternating periods of attraction and repulsion. When the pairs of swimmers are perpendicular to a nearby wall, for all cases considered, they approach the wall and reach a constant distance between swimmers. Interestingly, we observe sperm rolling in the case of swimmers with preferred planar beat forms that are initialized in parallel beat planes and near a wall.

Computational Study of Pressure Pulsation in a Medium Specific Speed Pump

2005 ◽  
Author(s):  
Serguei Timouchev
Keyword(s):  
Complex Geometry ◽  
Computational Study ◽  
Spectral Component ◽  
Axial Component ◽  
Centrifugal Pumps ◽  
Pressure Pulsations ◽  
3 Dimensional ◽  
Order Of Magnitude ◽  
Specific Speed ◽  
In The Beginning

The centrifugal pump of high specific speed with a diagonal type of impeller flow is studied experimentally and numerically. Both 2D and 3D numerical methods are used by applying acoustics–vortex equations. Increasing energetic parameters of centrifugal pumps requires a more complex geometry of the impeller and volute as one needs to raise the specific speed of the pump to provide a higher efficiency value. The pump of higher specific speed has an impeller with curved blades and diagonal meridional section. The flow outgoing the impeller has an essential axial component of velocity. Thus the two dimensional approach will not give the accurate prediction of pressure pulsations in the volute casing. This is why the new 3-dimensional method has been elaborated for this task. The 3D computational results of pressure pulsations are compared with those obtained by 2D-computation Measurements show that in the beginning of volute, in the pseudo-sound zone, amplitude of Blade Passing Frequency (BPF) spectral component is higher than that at the pump outlet by an order of magnitude. The 3-Dimensional analysis gives a good agreement with experimental data while the 2D prediction underestimates the BPF amplitude in the beginning of volute.

Computational Study of Single-Sided Ventilation Through a 3-Dimensional Room With Rounded Edges

2013 ◽  
Author(s):  
A. Idris ◽  
B. P. Huynh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Flow Pattern ◽  
Flow Rate ◽  
Software Package ◽  
Computational Study ◽  
Ventilation Rate ◽  
3 Dimensional ◽  
Computational Fluid Dynamics Cfd

A commercial Computational Fluid Dynamics (CFD) software package is used to investigate numerically a 3-dimensional rectangular-box room with rounded edges. The room has all its window openings located on one wall only. The standard K-ε turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. Especially, comparison with ventilation rate corresponding to when the room edges are sharp is made; and thereby the effects of the edges being rounded are examined.

scholarly journals Stabilization of the lumbar spine by spinal muscle forces producing compressive follower loads: 3-dimensional computational study

2018 ◽  
Vol 36 (11) ◽  
pp. 3004-3012 ◽  
Author(s):  
Tianjiao Foresto ◽  
InO Song ◽  
Byeong Sam Kim ◽  
Tae-Hong Lim
Keyword(s):  
Lumbar Spine ◽  
Computational Study ◽  
Muscle Forces ◽  
3 Dimensional

Computational Study of Single-Sided Ventilation Through a 3-Dimensional Room

2012 ◽  
Author(s):  
A. Idris ◽  
B. P. Huynh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Flow Rate ◽  
Software Package ◽  
Computational Study ◽  
Ventilation Rate ◽  
3 Dimensional ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through

Ventilation flow through a 3-dimensional rectangular-box room is investigated numerically, by using a commercial Computational Fluid Dynamics (CFD) software package. The room has all its window openings located on one wall, and the wind is assumed to blow parallel to this wall. The standard K-epsilon turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. For a constant total area of the openings, it is found that ventilation rate increases with more openings, especially when they are widely separated or positioned at different heights.

A 3-Dimensional Computational Study of Pulsating Flow Inside a Double Entry Turbine

2014 ◽  
Author(s):  
Peter Newton ◽  
Ricardo Martinez-Botas ◽  
Martin Seiler
Keyword(s):  
Mass Flow ◽  
Computational Study ◽  
Pulsating Flow ◽  
Test Facility ◽  
Entropy Generation Rate ◽  
Tip Leakage Flow ◽  
3 Dimensional ◽  
Rotor Wheel ◽  
Pulse Cycle ◽  
Double Entry

The double entry turbine contains two different gas entries, each feeding 180° of a single rotor wheel. This geometry can be beneficial for use in turbocharging and is uniquely found in this application. The nature of the turbocharging process means that the double entry turbine will be fed by a highly pulsating flow from the exhaust of an internal combustion engine, most often with out of phase pulsations in each of the two entries. Until now research on the double entry turbine under pulsating flow conditions has been limited to experimental work. Although this is of great value in showing how pulsating flow will affect the performance of the double entry turbine, the level of detail with which this can be studied is limited. This paper is the first to use a 3 dimensional computational analysis to study the flow structures within a double entry turbine under conditions of pulsating flow. The analysis looks at one condition of pulsating flow with out of phase pulsations. The computational results are validated against experimental data taken from the turbocharger test facility at Imperial College and a good agreement is found. The analysis first looks at the degree of mass flow storage within different components of the turbine and discusses the effect on the performance of the turbine. Each of the volute limbs is found to be subject to a large degree of mass storage throughout a pulse cycle demonstrating a definite impact of the unsteady flow. The rotor wheel shows a much smaller degree of mass flow storage overall due to the pulsating flow, however each rotor passage is subject to a much larger degree of mass flow storage due to the instantaneous flow inequality between the two volute inlets. This is a direct consequence of the double entry geometry. The following part of the analysis studies the loss profile within the turbine under pulsating flow using the concept of entropy generation rate. A significant change in the loss profile of the turbine is found throughout the period of a pulse cycle showing a highly changing flow regime. The major areas of loss are found to be due to tip leakage flow and mixing within the blade passage.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

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