Comparison of the Numerical and Experimental Flowfield Downstream of a Plate Array

2001 ◽  
Vol 124 (1) ◽  
pp. 284-286 ◽  
Author(s):  
D. W. Guillaume ◽  
J. C. LaRue
Keyword(s):  
Numerical Simulation ◽  
Axial Velocity ◽  
Thickness Ratio ◽  
Velocity Increase ◽  
Trailing Edges ◽  
Recirculation Zones ◽  
Plate Array ◽  
Adjacent Channels ◽  
Previous Experimental Study ◽  
Velocity Decrease

The findings of a numerical solution of the flowfield downstream of a six-plate array are compared to a previous experimental study. In both studies, the chord-to-thickness ratio, c/t, is 6.67, the Reynolds number, Re, is 500, and the spacing-to-thickness ratio, H/t, is 3.67. Consistent with experimental results, the numerical simulation shows that the recirculation zones formed at the trailing edges of the surfaces that form channels in the plate array are in-phase. Also consistent, they are nearly 180 deg out-of-phase with the recirculation zones formed at the trailing edges of the surfaces of adjacent channels. Comparison of the locations of recirculation zones and peaks in the downstream variation in axial velocity confirms that “vortex pumping” is described by 1) the axial velocity increase on the midplane of the channel in the region where the separation between pairs of recirculation zones is a minimum and 2) the axial velocity decrease in the region where the separation between pairs of recirculation zones is a maximum.

Synchronous Vortex Shedding (Vortex Pumping) Downstream of a Flat Plate Array

1999 ◽  
Vol 122 (1) ◽  
pp. 183-185 ◽  
Author(s):  
D. W. Guillaume ◽  
J. C. LaRue
Keyword(s):  
Flow Visualization ◽  
Vortex Pair ◽  
Flat Plates ◽  
Mean Velocity ◽  
Trailing Edges ◽  
The Mean ◽  
Plate Array ◽  
Adjacent Channels ◽  
Bounding Surfaces ◽  
Zero Time

Flow visualization and statistics, obtained downstream of an array of flat plates, are presented. Flow visualization shows that the mean separation between streaklines for the flow downstream of adjacent channels is negatively correlated. Consistent with this observation, the zero-time cross correlation of the fluctuating velocity between adjacent plates is negative. Vortices shed at the trailing edges of the bounding surfaces that form a channel in the plate array are in-phase, but they are nearly 180 deg out-of-phase with the vortices shed at the trailing edges of the bounding surfaces of adjacent channels. Relative to the mean velocity, the axial velocity on the midplane of the channel increased in the region between each pair of vortices. At downstream positions not near the vortex pair, the velocity on the midplane is relatively decreased. Hence, vortices shed at the trailing edges of the channel surfaces lead to “vortex pumping,” which is consistent with the negative correlation of the fluctuating velocity on the midplanes between adjacent channels. [S0098-2202(00)01701-6]

Numerical Simulation of Flow Field in Burnt Lime Hydrator

2011 ◽  
Vol 383-390 ◽  
pp. 2206-2210
Author(s):  
Ming Hua Bai ◽  
Yu Zhang ◽  
Qiu Fang Wang
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Flow Field ◽  
Velocity Gradient ◽  
Rotational Speed ◽  
Fugitive Dust ◽  
Work Condition ◽  
Burnt Lime ◽  
Stirring Effect ◽  
Recirculation Zones

The flow field distribution in burnt lime hydrator has been investigated by a software FLUENT, with k-ε turbulence model and MRF method. The simulation result shows that when four blades deflect 30°, the whole velocity gradient of flow reduces and the recirculation zones also diminish; when the rotational speed is 75r/min, the turbulence kinetic energy of stir zone between two axes becomes larger, which can raise stirring effect and reduce fugitive dust, so it is easy to achieve the purpose of improving the environment of work condition.

Analysis and Numerical Simulation of no Reacting Swirling Flow by Using URANS Approach

2021 ◽  
Vol 57 ◽  
pp. 67-79
Author(s):  
Merouane Habib ◽  
Senouci Mohammed
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Swirling Flow ◽  
Navier Stokes ◽  
Governing Equations ◽  
Simulation Based ◽  
Classical Models ◽  
Recirculation Zones ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Method

In this paper, we investigate the no-reacting swirling flow by using the numerical simulation based to the unsteady Reynolds-averaged Navier-Stokes approach. The numerical simulation was realized by using a computational fluid dynamics CFD code. The governing equations are solved by using the finite volume method with two classical models of turbulence K-epsilon and Shear Stress K-ω. The objective of this paper is therefore to evaluate the performance of the two models in predicting the recirculation zones in a swirled turbulent flow. The current models are validated by comparing the numerical results of the axial, radial and tangential velocities to the experimental data from literature.

Numerical Investigation for Fracture Saturation in Multilayer Sedimentary Rock in Unsymmetrical Case

2013 ◽  
Vol 690-693 ◽  
pp. 3050-3053
Author(s):  
Feng Shan Han ◽  
Li Song
Keyword(s):  
Numerical Simulation ◽  
Layer Thickness ◽  
Sedimentary Rock ◽  
Process Analysis ◽  
Failure Process ◽  
Bottom Layer ◽  
Thickness Ratio ◽  
Fracture Spacing ◽  
Layer Thickness Ratio ◽  
Rock Failure Process

Opening mode fractures in multilayer sedimentary rock often are periodically distributed with fracture spacing scaled to the thickness of the fractured layer. In this paper, based on Rock Failure Process Analysis Code RFPA2D, a three layer model with a central layer and with the different thickness top and bottom layer, progressive formation in multilayer sedimentary rock at fracture saturation in unsymmetrical case is simulated. We investigate the change of the critical fracture spacing to layer thickness ratio as a function of the thickness of the top layer where the bottom layers is much thicker (5 times) than the fractured layer called the unsymmetrical case, in this unsymmetrical case, fracture saturation is simulated. By numerical simulation of RFPA2D, the critical spacing to layer thickness ratio decreases and tend to the same constant value as the thickness of the top layer increases. Numerical simulation shown that for the unsymmetrical case, if the adjacent layers are thicker than 1.5 times the thickness of the fractured layer, the multilayer sedimentary rock can be treated approximately as a system with infinitely thick top and bottom layers at fracture saturation.That should be useful in the design of engineering systems and in the prediction of fracture spacing in hydrocarbon reservoirs and groundwater aquifers.

scholarly journals Effects of Shell on Bore center Annular Shaped Charges Formation and Penetrating into Steel Targets

2020 ◽  
Vol 70 (1) ◽  
pp. 35-40
Author(s):  
Wenlong Xu ◽  
Cheng Wang ◽  
Jianming Yuan ◽  
Weiliang Goh ◽  
Bin Xu
Keyword(s):  
Numerical Simulation ◽  
Radial Velocity ◽  
Numerical Simulations ◽  
Penetration Depth ◽  
Axial Velocity ◽  
Shaped Charge ◽  
Shell Structures ◽  
Steel Shell ◽  
Simulation Results ◽  
Good Agreement

Annular shaped charge can efficiently create large penetration diameter, which can solve the problem of small penetration diameter of a traditional shaped charge, and thus meeting the requirements of large penetration diameter in some specific situations. In this paper, the influence of five kinds shell structures, i.e. no shell, aluminum shell with thickness of 2.0 mm and steel shell with thickness of 2.0 mm, 3.0 mm and 4.0 mm, on bore-center annular shaped charges (BCASCs) formation and penetrating steel targets was investigated by numerical simulations and experiments. The numerical simulation results are in good agreement with the experimental results. The results showed that, from no shell to aluminum shell of 2.0 mm and then to steel shell of 2.0 mm, 3.0 mm and 4.0 mm for BCASCs, the diameter and radial velocity of projectile head decrease, the axial velocity of BCASC projectiles increases gradually, the penetration diameter of the targets decreases, and the penetration depth increases. The penetration diameter caused by the BCASC with no shell is the largest, being 116.0 mm (1.16D), D is the charge diameter. The penetration depth caused by the BCASC with steel shell of 4.0 mm thickness is the deepest, being 76.4 mm (0.76D).

scholarly journals Numerical simulation of vortices with axial velocity deficits

1995 ◽  
Vol 7 (3) ◽  
pp. 549-558 ◽  
Author(s):  
Saad Ragab ◽  
Madhu Sreedhar
Keyword(s):  
Numerical Simulation ◽  
Axial Velocity ◽  
Velocity Deficits

scholarly journals Three-dimensional numerical simulation of a turbulent flow around an obstacle

2020 ◽  
Vol 307 ◽  
pp. 01006
Author(s):  
Benahmed Lamia ◽  
Aliane Khaled ◽  
Z. Sari Hassoun
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Kinetic Energy ◽  
Three Dimensional ◽  
Governing Equations ◽  
Ansys Cfx ◽  
Recirculation Zones ◽  
Rectangular Obstacle ◽  
Volume Method ◽  
Calculation Code

In this work we study the influence of the inclined shape of the lover and downstream edge of a rectangular obstacle. We analyze the dimensions of the recirculation zones, the velocity field, the kinetic energy and the pressure. A three-dimensional study was conducted using the ansys cfx calculation code. The turbulence model k-ԑ is used to model turbulence, and the governing equations are resolved by the finite volume method.

Numerical Simulation of Flow Field in Bloom Continuous Casting Mold with Electromagnetic Stirring

2010 ◽  
Vol 146-147 ◽  
pp. 272-276 ◽  
Author(s):  
Jing Zhang ◽  
En Gang Wang ◽  
An Yuan Deng ◽  
Xiu Jie Xu ◽  
Ji Cheng He
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Flow Field ◽  
Continuous Casting ◽  
Tangential Velocity ◽  
Electromagnetic Stirring ◽  
Continuous Casting Mold ◽  
Frequency Increase ◽  
Velocity Increase ◽  
Casting Mold

A coupled numerical simulation of magnetic field and flow field was conducted basing on Φ250mm bloom during continuous casting with electromagnetic stirring.The distribution of the flow field was analyzed in different current and frequency.At the same current,the velocity first decrease and then increase as the frequency increase along the casting direction.At the same frequency, tangential velocity is dominant in the radial of EMS center,velocity increase with the current. Considered the results of numerical simulation,the optimized EMS parameters of Φ250mm bloom are the stirring current of 480A and the stirring frequency of 3Hz.

Experimental Study of the Effect of Serrations on Axial Flow Fan Blade Trailing Edge

2016 ◽  
Author(s):  
Dhyanjyoti Deb Nath ◽  
K. Viswanath ◽  
Ankit Bhai Patel
Keyword(s):  
Axial Velocity ◽  
Pressure Sensors ◽  
Tangential Velocity ◽  
Axial Flow ◽  
Experimental Investigations ◽  
Spanwise Direction ◽  
Axial Fan ◽  
Trailing Edge ◽  
Trailing Edges ◽  
Fan Blade

Rotor wakes shed from a compressor rotor impinge on downstream blades and is a major source of rotor-stator interaction noise and much research has been dedicated on wake attenuation. Serrated trailing edges is one such wake attenuation technique where the vortices produced at the serrated trailing edges enhance mixing and create a more uniform flow at stator inlet. The present paper investigates the effect of serrations on the trailing edge of a forced vortex axial fan blade. Experimental investigations were carried out at rotor outlet using pneumatic probes and fast response pressure sensors. It is found that total and static pressures reduce in serrated blades due to reduced turning and hence reduced work input. The absolute tangential velocity wake deficit decreases in serration valleys and improvement in axial velocity wake deficit is also found. Improvements as large as 19% and 18% decrease in absolute tangential velocity and axial velocity wake deficit are found at certain radii. The spanwise shape of the wake is altered by the serrations and a wake pattern undulating in the spanwise direction is observed. These are expected to bring down the circumferential variation of the velocity and its phase before entering the next row of blades and bring down the tonal noise.

Investigation Concerning Maximal Forming Depth of Tailor Welded Blanks Made from same Material but Different Thickness Ratios

2013 ◽  
Vol 371 ◽  
pp. 275-279
Author(s):  
Aurelian Albut
Keyword(s):  
Numerical Simulation ◽  
Significant Relationship ◽  
Thin Sheet ◽  
Surface Characteristics ◽  
Thickness Ratio ◽  
Uniform Deformation ◽  
Tailor Welded Blanks ◽  
Property Changes ◽  
Forming Behaviour ◽  
Different Thickness

The formability of tailor welded blanks is significantly reduced compared with the homogeneous blanks. Some of the important factors that are behind this fact are: material property changes in the weld and the heat-affected zones, non-uniform deformation because of the differences in thickness, properties and/or surface characteristics and location and orientation of the weld with respect to the direction of application of load. The objective of this resarch work is to establish a relation between thickness ratio and maximal forming depth in TWBs made from same material but having different thickness. For the numerical simulation it was considered a rectangular workpiece with dimensions: 147,8mm x 147,8mm. Depending on the thickness value of the blank, the design of the working tools must be modified the dimensions of the punch using the same die for all simulations. During the simulation the FLD predict de forming behaviour of the metal sheet. For this study there was not a statistically significant relationship between maximal forming depth and thickness ratio of the tailor welded blanks. But it was possible to generate fitted models, that are parabolic relations, starting with the maximal forming depth for ratio 1 (homogeneous sheet), when the ratio increases, firstly the maximal forming depth decreases until one point where the tendency changes and lately increases, and the maximal forming depth achieves values even higher than the initials. Also it can be said that the thicker is the thin sheet the closer is the parabolic fitted form.

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