scholarly journals 916 Large Scale Flow Analysis by SMAC-SPH Method using PC Clusters

2005 ◽  
Vol 2005.18 (0) ◽  
pp. 579-580 ◽  
Author(s):  
Yuzuru SAKAI ◽  
Jun IMASATO ◽  
Shunta KAWASAKI ◽  
Nobuki YAMAGATA
2012 ◽  
Vol 212-213 ◽  
pp. 201-204
Author(s):  
Wei Gang Xu ◽  
Hua Yong Zhang ◽  
Zhong Yu Wang ◽  
Wen Pei Huang

The flow field of constructed wetland plays an important role in wetland stabilization and efficient operation. TengZhou Quanshang constructed wetland was taken as the research object. The RNG k-ε two-equation turbulence model equations coupling with the volume of fluid (VOF) model are introduced to simulation the vegetation cover flow. And the flow velocities of 37 measured points in wetland were measured by using the ADV instrument. Then the simulation velocity was compared with the field measured velocity. The results are shown to be satisfactory, and basically meet the large-scale flow analysis requirements. The problems of flow field distribution on the initial state was analyzed and optimized. The uniformity of velocity in wetland increased, and water mobility improved after optimization. Our results provide guidance for the 2D water quality simulation, pollutants migration and combination of plant purification effect in natural and constructed wetland.


Talanta ◽  
2021 ◽  
pp. 122479
Author(s):  
Elias A.G. Zagatto ◽  
Fábio R.P. Rocha

2005 ◽  
Vol 33 (1) ◽  
pp. 38-62 ◽  
Author(s):  
S. Oida ◽  
E. Seta ◽  
H. Heguri ◽  
K. Kato

Abstract Vehicles, such as an agricultural tractor, construction vehicle, mobile machinery, and 4-wheel drive vehicle, are often operated on unpaved ground. In many cases, the ground is deformable; therefore, the deformation should be taken into consideration in order to assess the off-the-road performance of a tire. Recent progress in computational mechanics enabled us to simulate the large scale coupling problem, in which the deformation of tire structure and of surrounding medium can be interactively considered. Using this technology, hydroplaning phenomena and tire traction on snow have been predicted. In this paper, the simulation methodology of tire/soil coupling problems is developed for pneumatic tires of arbitrary tread patterns. The Finite Element Method (FEM) and the Finite Volume Method (FVM) are used for structural and for soil-flow analysis, respectively. The soil is modeled as an elastoplastic material with a specified yield criterion and a nonlinear elasticity. The material constants are referred to measurement data, so that the cone penetration resistance and the shear resistance are represented. Finally, the traction force of the tire in a cultivated field is predicted, and a good correlation with experiments is obtained.


2001 ◽  
Vol 9 (1) ◽  
pp. 3-7
Author(s):  
Damon Liu ◽  
Mark Burgin ◽  
Walter Karplus ◽  
Daniel Valentino

Author(s):  
Yanzhe Sun ◽  
Kai Sun ◽  
Tianyou Wang ◽  
Yufeng Li ◽  
Zhen Lu

Emission and fuel consumption in swirl-supported diesel engines strongly depend on the in-cylinder turbulent flows. But the physical effects of squish flow on the tangential flow and turbulence production are still far from well understood. To identify the effects of squish flow, Particle image velocimetry (PIV) experiments are performed in a motored optical diesel engine equipped with different bowls. By comparing and associating the large-scale flow and turbulent kinetic energy (k), the main effects of the squish flow are clarified. The effect of squish flow on the turbulence production in the r−θ plane lies in the axial-asymmetry of the annular distribution of radial flow and the deviation between the ensemble-averaged swirl field and rigid body swirl field. Larger squish flow could promote the swirl center to move to the cylinder axis and reduce the deformation of swirl center, which could decrease the axial-asymmetry of annular distribution of radial flow, further, that results in a lower turbulence production of the shear stress. Moreover, larger squish flow increases the radial fluctuation velocity which makes a similar contribution to k with the tangential component. The understanding of the squish flow and its correlations with tangential flow and turbulence obtained in this study is beneficial to design and optimize the in-cylinder turbulent flow.


2012 ◽  
Vol 37 (1) ◽  
pp. 894-902 ◽  
Author(s):  
Jianjun Ye ◽  
Jian Yang ◽  
Jinyang Zheng ◽  
Xianting Ding ◽  
Ieong Wong ◽  
...  

2016 ◽  
Vol 794 ◽  
Author(s):  
Antoine Campagne ◽  
Nathanaël Machicoane ◽  
Basile Gallet ◽  
Pierre-Philippe Cortet ◽  
Frédéric Moisy

What is the turbulent drag force experienced by an object moving in a rotating fluid? This open and fundamental question can be addressed by measuring the torque needed to drive an impeller at a constant angular velocity ${\it\omega}$ in a water tank mounted on a platform rotating at a rate ${\it\Omega}$. We report a dramatic reduction in drag as ${\it\Omega}$ increases, down to values as low as 12 % of the non-rotating drag. At small Rossby number $Ro={\it\omega}/{\it\Omega}$, the decrease in the drag coefficient $K$ follows the approximate scaling law $K\sim Ro$, which is predicted in the framework of nonlinear inertial-wave interactions and weak-turbulence theory. However, stereoscopic particle image velocimetry measurements indicate that this drag reduction instead originates from a weakening of the turbulence intensity in line with the two-dimensionalization of the large-scale flow.


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