Numerical Study on Flow around Three Circular Piers in Tandem Arrangement at a Supercritical Reynolds Number

2012 ◽  
Vol 170-173 ◽  
pp. 1932-1937
Author(s):  
Peng Hao ◽  
Guo Dong Li ◽  
Lan Yang ◽  
Gang Chen
Keyword(s):  
Reynolds Number ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Two Dimensional ◽  
Lateral Loads ◽  
Dynamic Design ◽  
Tandem Arrangement ◽  
Dynamic Forces ◽  
Les Model ◽  
Supporting Structures

As the support structures of building for crossing river, piers of bridge and/or aqueduct are generally arranged in tandem along the river direction, the fluid dynamic forces are main lateral loads acting on the Piers. Two-dimensional fluid computations have been performed using LES model to investigate the flows around three circular piers in tandem arrangements at a supercritical Reynolds number, Re =8.76×106. Both center-to-center spaces are L/D=2.6. The flows and fluid-dynamic forces obtained from the simulations are analyzed. The results can provide the basis for the dynamic design of the supporting structures of the aqueducts.

Numerical Study on Heat Transfer Characteristics From Parallel Plates With Cavities Swept by a Visco-Elastic Fluid

2010 ◽  
Author(s):  
Hiroshi Suzuki ◽  
Shinpei Maeda ◽  
Yoshiyuki Komoda
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Thermal Field ◽  
Numerical Study ◽  
Geometric Parameters ◽  
Two Dimensional ◽  
Parallel Plates ◽  
Heat Transfer Characteristics ◽  
Elastic Fluid ◽  
Heat Transfer Augmentation

Two-dimensional numerical computations have been performed in order to investigate the development characteristics of flow and thermal field in a flow between parallel plates swept by a visco-elastic fluid. In the present study, the effect of the cavity number in the domain and of Reynolds number was focused on when the geometric parameters were set constant. From the results, it is found that the flow penetration into the cavities effectively causes the heat transfer augmentation in the cavities in any cavity region compared with that of water case. It is also found that the development of thermal field in cases of the present visco-elastic fluid is quicker compared with that of water cases. The present heat transfer augmentation technique using Barus effect of a visco-elastic fluid is effective in the range of low Reynolds number.

Experiments on the lift and drag of spheres suspended in a Poiseuille flow

1964 ◽  
Vol 20 (3) ◽  
pp. 513-527 ◽  
Author(s):  
R. Eichhorn ◽  
S. Small
Keyword(s):  
Reynolds Number ◽  
Poiseuille Flow ◽  
Rotation Speed ◽  
Fluid Dynamic ◽  
Particle Diameter ◽  
Dynamic Forces ◽  
Shear Parameter ◽  
Fluid Properties ◽  
Approach Velocity ◽  
Lift And Drag

An experimental investigation of the fluid dynamic forces on spheres suspended in a Poiseuille flow was performed. Small spheres of polystyrene, nylon, and Lucite, having diameters ranging from 0.061 in. to 0.126 in. were suspended in Poiseuille flows in a 0.419 in. diameter tube. Variations in particle size and density, the fluid properties, and the angle of inclination of the tube, resulted in a sphere Reynolds number (based on particle diameter and approach velocity) ranging from 80 to 250. The results are presented as curves which include the coefficients of lift and drag, and the dimensionless rotation speed plotted versus Reynolds number and a dimensionless shear parameter.

scholarly journals Numerical Study of Flow Characteristics Around Confined Cylinder using OpenFOAM

2018 ◽  
Vol 7 (4.35) ◽  
pp. 617
Author(s):  
P. Mathupriya ◽  
L. Chan ◽  
H. Hasini ◽  
A. Ooi
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Numerical Study ◽  
Vortex Formation ◽  
Plane Channel ◽  
Flow Characteristics ◽  
Strong Interactions ◽  
Two Dimensional ◽  
Computational Fluid Dynamics Cfd ◽  
Shedding Frequency

The numerical study of the flow over a two-dimensional cylinder which is symmetrically confined in a plane channel is presented to study the characteristics of vortex shedding. The numerical model has been established using direct numerical simulation (DNS) based on the open source computational fluid dynamics (CFD) code named OpenFOAM. In the present study, the flow fields have been computed at blockage ratio, β of 0.5 and at Reynolds number, Re of 200 and 300. Two-dimensional simulations investigated on the effects of Reynolds number based on the vortex formation and shedding frequency. It was observed that the presence of two distinct shedding frequencies appear at higher Reynolds number due to the confinement effects where there is strong interactions between boundary layer, shear layer and the wake of the cylinder. The range of simulations conducted here has shown to produce results consistent with that available in the open literature. Therefore, OpenFOAM is found to be able to accurately capture the complex physics of the flow.

LATTICE BOLTZMANN SIMULATION OF TWO-DIMENSIONAL WALL BOUNDED TURBULENT FLOW

2010 ◽  
Vol 21 (05) ◽  
pp. 669-680 ◽  
Author(s):  
GÁBOR HÁZI ◽  
GÁBOR TÓTH
Keyword(s):  
Reynolds Number ◽  
Power Law ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Power Laws ◽  
Energy Spectra ◽  
Small Scale ◽  
Two Dimensional ◽  
Lattice Boltzmann Simulation ◽  
Decaying Turbulence

This paper reports on a numerical study of two-dimensional decaying turbulence in a square domain with no-slip walls. The generation of strong small-scale vortices near the no-slip walls have been observed in the lattice Boltzmann simulations just like in earlier pseudospectral calculations. Due to these vortices the enstrophy is not a monotone decaying function of time. Considering a number of simulations and taking their ensemble average, we have found that the decay of enstrophy and that of the kinetic energy can be described well by power-laws. The exponents of these laws depend on the Reynolds number in a similar manner than was observed before in pseudospectral simulations. Considering the ensemble averaged 1D Fourier energy spectra calculated along the walls, we could not find a simple power-law, which fits well to the simulation data. These spectra change in time and reveal an exponent close to -3 in the intermediate and an exponent -5/3 at low wavenumbers. On the other hand, the two-dimensional energy spectra, which remain almost steady in the intermediate decay stage, show clear power-law behavior with exponent larger than -3 depending on the initial Reynolds number.

Numerical Study of Two-Dimensional Turbulent Jets

2006 ◽  
Author(s):  
Tarek Abdel-Salam ◽  
Gerald Micklow ◽  
Keith Williamson
Keyword(s):  
Reynolds Number ◽  
Numerical Analysis ◽  
Numerical Study ◽  
Turbulent Jets ◽  
Parallel Plane ◽  
Two Dimensional ◽  
Reattachment Point ◽  
Wall Angle ◽  
Plane Jets ◽  
Turbulent Plane

The current study reports numerical analysis of turbulent jets. Effects of various parameters on the characteristics of two-dimensional turbulent plane parallel and offset jets are investigated. The emphasis is put on the effect of the wall angle and nozzle width on the location merging and the combining points. The flowfield under consideration are two-parallel plane jets and offset jets issued from plane wall. Four angles and three values of the nozzle width are used. Also, different values of Reynolds number between 9000 and 39000 have been examined. It is noted that the wall angle and the nozzle width linearly affect the location of the merging and the combining points, while Reynolds number plays no role in their location. The effect of the wall angle on the reattachment point is found to be non linear.

Numerical Study of Flow and Heat Transfer Characteristics of Impinging Jets

2010 ◽  
Author(s):  
Tarek M. Abdel-Salam
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Numerical Study ◽  
Three Dimensional ◽  
Impinging Jets ◽  
Two Dimensional ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer

This study presents results for flow and heat transfer characteristics of two-dimensional rectangular impinging jets and three-dimensional circular impinging jets. Flow geometries under consideration are single and multiple impinging jets issued from a plane wall. Both confined and unconfined configurations are simulated. Effects of Reynolds number and the distance between the jets are investigated. Results are obtained with a finite volume computational fluid dynamics (CFD) code. Structured grids are used in all cases of the present study. Turbulence is treated with a two equation k-ε model. Different jet velocities have been examined corresponding to Reynolds numbers of 5,000 to 20,000. Results of the three-dimensional cases show that Reynolds number has no effect on the velocity distribution of the center jet. Results of both two-dimensional and three-dimensional cases show that Reynolds number highly affects the heat transfer and values of the Nusselt number. The maximum Nusselt number was always found at the stagnation point of the center jet.

K-1229 Turbulence-Induced Fluid Dynamic Forces Acting on Cross-Shaped Tube Bundle in Cross Flow : Part 2 : Measurement in the High Reynolds Number

2001 ◽  
Vol V.01.1 (0) ◽  
pp. 139-140
Author(s):  
Takashi NISHIHARA ◽  
Nobukazu TANAKA ◽  
Fumio INADA ◽  
Akira YASUO ◽  
Shinichi KAWAMURA ◽  
...  
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Tube Bundle ◽  
Fluid Dynamic ◽  
Cross Flow ◽  
Shaped Tube ◽  
Dynamic Forces ◽  
Flow Part ◽  
High Reynolds

Numerical Study of Cage Dynamics Focused on Hydrodynamic Effects of Guidance Land Clearances for Different Ball-Pocket Clearances in Cryogenic Environments

2017 ◽  
Author(s):  
Bok Seong Choe ◽  
Jeon Kook Lee ◽  
Doyoung Jeon ◽  
Yongbok Lee
Keyword(s):  
Ball Bearing ◽  
Rotation Speed ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Operating Conditions ◽  
Cfd Analysis ◽  
Dynamic Motion ◽  
Light Load ◽  
Dynamic Forces ◽  
Inner Race

This study presents the dynamic motion of a ball bearing cage submerged in a cryogenic fluid under high-speed conditions. The dynamic motion of the cage has been studied as a function of the race land–cage and ball–cage pocket clearances for different inner race rotation speeds under light load conditions. In addition, this study conducted computational fluid dynamics (CFD) analysis using commercial software to analyze the fluid dynamic forces on the cage. The hydraulic force obtained from the CFD analysis was coded in commercial ball bearing analysis software as a function of the eccentricity ratio and rotation speed of the cage. Finally, the dynamic motion of the ball bearing cage considering the effects of fluid dynamic forces has been studied. The results include the cage whirling amplitude, fluctuation of cage whirling speed, and cage wear for various cage clearances and rotation speeds. The cage outer guidance clearances studied were 1.14, 1.04, 0.94, 0.84, and 0.74 mm and the ball–pocket clearances were 0.62, 0.92, 1.22, 1.52, and 1.82 mm. The rotation speeds of the inner race were 5,000, 8,000, and 11,000 rpm. The cage whirling amplitude decreases as the outer guidance clearance decreases, and it decreases as the rotation speed increases up to 11,000 rpm because of the increasing hydrodynamic force of the liquid nitrogen (LN2). However, the probability density function (PDF) curves indicate that an increase in the rotor speed increases the standard deviation in the cage whirling frequency. The wear loss of the cage was greatest for the largest race land–cage and the smallest ball–cage pocket clearances, owing to the increased number of intermittent collisions between the cage and the ball bearings (ball–race). Consequently, the analysis results for various operating conditions (inner race rotation speeds, cage clearances, traction coefficients, etc.) are in good agreement with the reference results.

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