scholarly journals LES of spray in crossflow – Effect of droplet distortion

2016 ◽  
Vol 9 (1) ◽  
pp. 55-70 ◽  
Author(s):  
Anubhav Sinha ◽  
RV Ravikrishna
Keyword(s):  
Initial Conditions ◽  
Spherical Shape ◽  
Experimental Results ◽  
Mass System ◽  
Large Eddy ◽  
Droplet Sizes ◽  
Experimental Values ◽  
Early Breakup ◽  
Drag Law ◽  
Good Agreement

The present investigation is focused on modeling of spray in crossflow using Large Eddy Simulations (LES). The modeling efforts are supported by experiments which are used both to provide accurate boundary and initial conditions and to evaluate droplet shapes in the near nozzle region. The droplets are modeled as Lagrangian parcels in an Eulerian continuum. Droplets in such configuration have been found to be distorted and not in perfect spherical shape from experimental results of our previous study. Droplet distortion is computed by Taylor-Analogy Breakup (TAB) distortion model. Each droplet is modelled as damped spring-mass system, where surface tension acts as a spring on the mass of the droplet and viscous dissipation provides the damping effect. The effort is to examine the effect of drag law used and the effect of this distortion on the droplet sizes produced in the flow field. Spray wind-ward trajectory and droplet sizes obtained from simulations are compared with the experimental results available. Although computational spray trajectory shows a reasonable match with experimental values, droplet sizes using the standard TAB model are found to be larger than that from experimental observation. To account for this distortion and its role in early breakup of droplets, constants of the TAB model are modified and the droplet sizes are found to be in good agreement with the experimental data.

Atomistic Simulation for the Site Preference of Tb3(Fe28-XCoX)V1.0 Compounds

2012 ◽  
Vol 535-537 ◽  
pp. 1015-1018
Author(s):  
Jing Sun ◽  
Shuo Huang ◽  
Jiang Shen ◽  
Ping Qian
Keyword(s):  
Rare Earth ◽  
Structural Properties ◽  
Atomistic Simulation ◽  
Experimental Results ◽  
Inversion Method ◽  
Site Preference ◽  
Lattice Constants ◽  
Pair Potentials ◽  
Experimental Values ◽  
Good Agreement

The effect of cobalt on the structural properties of intermetallic Tb3(Fe28-xCox)V1.0with Nd3(Fe,Ti)29structure has been studied by using interatomic pair potentials obtained through the lattice inversion method. Calculated results show that the order of site preference of cobalt is 8j(Fe8), 4e(Fe11) and 2c(Fe1) which is in good agreement with experimental results. And the calculated lattice constants coincide quite well with experimental values. All these prove the effectiveness of interatomic pair potentials obtained through the lattice inversion method in the description of rare-earth materials.

Theoretical Investigation of the Switching Mechanism in a Bistable Wall Attachment Fluid Amplifier

1971 ◽  
Vol 93 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. Epstein
Keyword(s):  
Theoretical Investigation ◽  
Experimental Results ◽  
Turbulent Jet ◽  
Switching Behavior ◽  
Switching Mechanism ◽  
Switching Times ◽  
Experimental Values ◽  
End Wall ◽  
Good Agreement

A theory based on turbulent jet entrainment properties is presented for the prediction of unsteady end wall switching behavior in a bistable wall attachment fluid amplifier. Good agreement is obtained between theoretically predicted switching times and experimental results. The analysis also indicates the experimentally observed dwell phenomena and computed dwell times compare well with reported experimental values.

Understanding of flow features over a typical crew module at Mach 4

2015 ◽  
Vol 119 (1216) ◽  
pp. 727-746 ◽  
Author(s):  
S. L. N. Desikan ◽  
M. M. Patil ◽  
S. Subramanian
Keyword(s):  
Experimental Results ◽  
Leeward Side ◽  
Wake Vortex ◽  
Aerodynamic Coefficients ◽  
Near Wake ◽  
Sonic Line ◽  
Oil Flow ◽  
Flow Features ◽  
Experimental Values ◽  
Good Agreement

AbstractThis paper presents the numerical simulations of flowfield over a typical Crew Module at Mach 4 for different angles-of-attack ranging from 0 to –25°. Detailed flow features such as contour of density gradient over the model, numerical oil flow and near wake vortex structures are captured very well in the present simulations. The location of the sonic line and its behaviour due to angles-of-attack is also captured in the simulations. TheCPdistribution on the windward and leeward side shows excellent match with the experimental results. Also, the prediction of aerodynamic coefficients shows very good agreement with the experimental results. The numerical simulation predictsCMcg,CNandCAwithin 8%, 4% and 3·5% respectively with respect to experimental values.

Modeling and Dynamic Evaluation of a Two-Stage Two-Spool Servovalve Used for Pressure Control

1991 ◽  
Vol 113 (4) ◽  
pp. 709-713 ◽  
Author(s):  
S. T. Tsai ◽  
A. Akers ◽  
S. J. Lin
Keyword(s):  
Mathematical Model ◽  
Control Valve ◽  
Pressure Control ◽  
Experimental Results ◽  
Two Stage ◽  
Dynamic Evaluation ◽  
Second Stage ◽  
Experimental Values ◽  
Pressure Control Valve ◽  
Good Agreement

Experimental results for a unique design of a two-spool pressure control valve were reported by Anderson (1984). The first stage is a dynamically stable flapper-nozzle valve for which a mathematical model is already available (Lin and Akers, 1989a). For the second stage, however, which consists of two parallel spools in a common body, no such model existed. The purpose of this paper was therefore to construct such a model and to compare results calculated from it to experimental values. Moderately good agreement with experimental values was obtained.

Fluid Drag on a Sphere Rolling in a Tube

1967 ◽  
Vol 34 (3) ◽  
pp. 538-540
Author(s):  
A. B. Bauer ◽  
R. A. DuPuis
Keyword(s):  
Incompressible Fluid ◽  
Drag Force ◽  
Reynolds Numbers ◽  
Vertical Tube ◽  
Experimental Results ◽  
Constant Speed ◽  
Sphere Diameter ◽  
Fluid Drag ◽  
Drag Law ◽  
Good Agreement

The incompressible fluid drag force on a sphere rolling at constant speed in a closed-end tube has been analyzed for the case where the tube inside diameter is only slightly larger than the sphere diameter. One drag law is found for Reynolds numbers much less than 75π/4λ1/2, where λ is a parameter defined by the sphere and tube diameters. A second drag law is found for Reynolds numbers much larger than 75π/4λ1/2. Experimental results show good agreement with these drag laws. The first law is almost identical with the results of Christopherson and Dowson, and of McNown, et al., for a sphere falling in a vertical tube.

Study on Absorption Rate of Phosphorus for Hypereutectic Al-Si Alloy Modified with Cu-P

2014 ◽  
Vol 794-796 ◽  
pp. 112-117 ◽  
Author(s):  
Gu Zhong ◽  
Zhi Bin Wu ◽  
Chu Qiu ◽  
Ya Fang Li ◽  
Hiromi Nagaumi
Keyword(s):  
Process Parameters ◽  
Master Alloy ◽  
Absorption Rate ◽  
Reaction Rate ◽  
Process Condition ◽  
Experimental Results ◽  
Degree Of Reaction ◽  
Experimental Values ◽  
Good Agreement

In this paper, the effects of process parameters on the absorption rate of P for hypereutectic Al-Si alloy (A390) which modified with Cu-14%P master alloy were systematically studied. And the mechanism that the process parameters play a role in effecting on the absorption rate of P was deeply investigated. The results indicated that the absorption rate of P increased with the increase of modified time and temperature, and decreased with the increase of the amount of added P. Under the same process condition, P added in form of Cu-14%P particles can cause to obtain the higher absorption rate of P than that of Cu-14%P powders. According to the experimental results, an equation on changes of the absorption rate of P was proposed, and the results show that good agreement is obtained between calculated and experimental values. The process parameters played a role in effecting on the absorption rate of P mainly through affecting the reaction rate of forming AlP particles in the melt, as well as the degree of reaction reached.

Separation of CO2 by Using Aqueous Mixtures of AMP and [B3MPYR][BF4] at High Pressure

2014 ◽  
Vol 67 (4) ◽  
Author(s):  
Syamila Nordin ◽  
Ruzitah Mohd Salleh ◽  
Norhuda Ismail
Keyword(s):  
Absorption Capacity ◽  
Experimental Results ◽  
Co2 Absorption ◽  
Loading Capacity ◽  
Aqueous Mixtures ◽  
Simple Correlation ◽  
Separation Of Co2 ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

In this study, CO2 absorption capacity in aqueous mixtures of 2-amino-2-methyl-1-propanol, (AMP) and N-butyl-3-methylpyridinium tetrafluoroborate, [B3MPYR][BF4] was measured at pressures from 200 kPa up to 5000 kPa and temperatures of 303.15 K - 333.15 K. The AMP concentration was maintained at 1 M while the [B3MPYR][BF4] concentration ranges from 0.05 M to 0.3 M. It was observed that CO2 loading capacity increases when the pressure increased. However, increasing of temperature will decrease the CO2 loading. From the experimental results, a simple correlation, as suggested by Jou and Mather was used to predict the CO2 loading in the aqueous AMP-[B3MPYR][BF4] mixtures. The model were found to be in a good agreement with the experimental results where only 1.66% of the predicted values deviate more than 20% compared to the experimental values.

Rayleigh–Taylor mixing between density stratified layers

2016 ◽  
Vol 810 ◽  
pp. 584-602 ◽  
Author(s):  
R. J. R. Williams
Keyword(s):  
Initial Conditions ◽  
Mixing Layer ◽  
Configurational Entropy ◽  
Experimental Results ◽  
Numerical Calculations ◽  
Fluid Mixing ◽  
Late Time ◽  
Density Profiles ◽  
Rayleigh Taylor Instability ◽  
Good Agreement

We have performed numerical calculations of fluid mixing driven by Rayleigh–Taylor instability for density profiles based on the stratified density experiments of Lawrie & Dalziel (J. Fluid Mech., vol. 688, 2011, pp. 507–527) and Davies Wykes & Dalziel (J. Fluid Mech., vol. 756, 2014, pp. 1027–1057). We find that the late-time mixing profiles are similar to their experimental results for similar initial conditions; we consider a range of additional initial conditions to investigate the robustness of the results. A model for the late-time structure of the mixing layer, based on the maximization of configurational entropy, is compared with the results of the numerical calculations, and shows good agreement.

Assessment of the capabilities of FireFOAM to model large-scale fires in a well-confined and mechanically ventilated multi-compartment structure

2017 ◽  
Vol 36 (1) ◽  
pp. 3-29 ◽  
Author(s):  
Duy Le ◽  
Jeffrey Labahn ◽  
Tarek Beji ◽  
Cecile B Devaud ◽  
Elizabeth J Weckman ◽  
...  
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Large Scale ◽  
Detailed Comparison ◽  
Equation Model ◽  
Mechanically Ventilated ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Experimental Values ◽  
Good Agreement

This article presents a large eddy simulation study of a pool fire in a well-confined and mechanically ventilated multi-room configuration. The capabilities of FireFOAM are assessed by comparing the numerical results to a well-documented set of experimental data available from Propagation d’un Incendie pour des Scénarios Multi-locaux Elémentaires. The eddy dissipation concept, finite volume discrete ordinate method, and one k-equation model are used for combustion, thermal radiation, and sub-grid scale closure, respectively. The main boundary conditions are imposed based on the experimental profiles. A detailed comparison is made with available experimental data. Good agreement between the large eddy simulation results and experimental values is achieved for temperatures, velocity, CO2 volume concentrations, and pressures for most compartments. There are some noticeable underpredictions of temperature in the outlet room. Overall, FireFOAM is shown to have good predictive capabilities for the present confined large-scale fire scenario.

scholarly journals Isomer ratios for the 88Sr(p,xn) and 88Sr(p,p3n) reactions

1967 ◽  
Vol 45 (22) ◽  
pp. 2711-2721 ◽  
Author(s):  
D. R. Sachdev ◽  
L. Yaffe
Keyword(s):  
Statistical Model ◽  
Spin Density ◽  
Cross Section ◽  
Experimental Results ◽  
Density Parameter ◽  
Model Calculations ◽  
Experimental Values ◽  
Parameter Values ◽  
Good Agreement

Isomeric cross-section ratios for nuclides formed from (p,2n), (p,3n), (p,4n), and (p,p3n) reactions on 88Sr are presented. The experimental results for the 88Sr(p,2n)87Ym,g reaction are compared with statistical-model calculations wherein spin-density parameter values were obtained from various theoretical formalisms. The parameters required to match the calculated and experimental values are in good agreement with those obtained by Vandenbosch et al.

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