Direct Testing of a Three-Dimensional Model of the Planetary Boundary Layer Against Experimental Data

1978 ◽  
Vol 35 (1) ◽  
pp. 25-39 ◽  
Author(s):  
Gilles Sommeria ◽  
Margaret A. LeMone
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Direct Testing

The Use of Subgrid Transport Equations in a Three-Dimensional Model of Atmospheric Turbulence

1973 ◽  
Vol 95 (3) ◽  
pp. 429-438 ◽  
Author(s):  
J. W. Deardorff
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Transport Equations ◽  
Subgrid Scale ◽  
Reynolds Stresses ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Truncation Errors ◽  
Subgrid Scales ◽  
Grid Points

A three-dimensional numerical model of turbulence in an atmospheric boundary layer has been revised to utilize subgrid transport equations for the subgrid Reynolds stresses and fluxes rather than subgrid eddy coefficients. It was applied to a daytime boundary layer over heated ground in a region of horizontal area 8km square and 2km deep, utilizing 40×40×40 grid points. The constraints involved in selecting four important subgrid closure constants are discussed in some detail, along with maintenance of realizability on the subgrid scale. The results indicate that the subgrid transport equations produce subgrid Reynolds stresses and fluxes which realistically simulate the transfer of larger scale variance to subgrid scales, provided truncation errors due to advective terms are not too large. They also show the superiority of this method over the use of (nonstability dependent) nonlinear eddy coefficients in maintaining the sharpness of the inversion base which lies above the mixed layer.

The Numerical Simulation Research of Gas Entrainment Based on Three-Dimensional Model

2017 ◽  
Author(s):  
Yilin Zhang ◽  
Shanfang Huang
Keyword(s):  
Experimental Data ◽  
Mass Flow Rate ◽  
Cross Section ◽  
Flow Rate ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Gas Entrainment ◽  
Simulation Results

Two kinds of three-dimensional model are built to simulate the gas entrainment process through a small break in the horizontal coolant pipe at the bottom of the stratified flow. The results were compared with the two-dimensional simulation results and the experimental data. In terms of the two-phase distribution, the simulation results agree well with the experimental data and show much superiority compared with the two-dimensional model. The results verify the reliability of model building, condition setting and calculating method qualitatively and quantitatively. In general, after gas entrainment, the average velocity over cross section increases obviously, but the mass flow rate decreases contrarily. This is because that void fraction meanwhile reduces the fluid density. In addition, it is found that the larger the void fraction of vapor is, the higher the average discharge velocity of the fracture cross-section fluid is. Besides, with the larger internal and external pressure difference, the gas volume fraction and the flow velocity in the break increase, resulting in the mass flow rate increasing along with them. However, since the critical height increases as well, the total loss amount of liquid in the stable effluent stage decreases, and the time before entrainment becomes shorter.

Numerical and Experimental Analysis for Large Radius Deformation of Stainless Steels by Laser Forming Process

2005 ◽  
Author(s):  
J. Pennuto ◽  
J. Choi
Keyword(s):  
Experimental Data ◽  
Phase Transformation ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Laser Forming ◽  
Bend Angle ◽  
Large Radius ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Forming Process

In an effort to develop a process free of dedicated tooling, this research seeks to study large radius deformation by laser forming. Experimental testing was conducted to determine how the laser parameters affect the single pass output bend angle as well as the additive bend angle from successive parallel, evenly spaced laser irradiations. As an extension of the previous developments, this work seeks to develop a three-dimensional model to simulate the multi-scan laser process. It is of interest to determine how sophisticated a three-dimensional case is required for sufficient agreement to experimental data. The simulated results of bending angle are compared with experimental data and suggestions for future study include the implementation of phase transformation and microstructure data within the model to account for stress development resulting from phase transformation and grain growth.

Liquid Flow Characteristics in Microchannels

2011 ◽  
Vol 130-134 ◽  
pp. 1484-1490
Author(s):  
Yan Feng Liu ◽  
Hong Wei Li ◽  
Jing Wei Zhang ◽  
Jin Xue
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Fluid Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Simulation Methods ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Simulation Results ◽  
Poiseuille Number

A three-dimensional model was developed to simulate the laminar flow and convective heat transfer in rectangular silicon microchannels，which have hydraulic diameter of 95.3，92.3 ,85.8 , 80 and 75μm respectively．The rationality of the simulation methods and results were validated by comparing with experimental data. The simulation results indicate that the aspect ratio has a significant impact on the Poiseuille number. Conventional fluid flow theory is fit for researching the fluid flow in microchannels, Po is a constant that is not dependent on the Reynolds number.

Numerical Analysis of Cone-Jet Based on EHD Micro-Jet Technology

2015 ◽  
Vol 713-715 ◽  
pp. 323-326
Author(s):  
Sha Sha Wang ◽  
Zheng Ning Tang ◽  
Bin Ying Miao ◽  
Jia Xiang Chen
Keyword(s):  
Experimental Data ◽  
High Resolution ◽  
Theoretical Basis ◽  
Simple Structure ◽  
High Efficiency ◽  
Three Dimensional ◽  
Cost Effective ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Functional Patterns

EHD micro-jet can deposit rule and functional patterns in a direct, continuous and controllable manner, and has the advantages of good compatibility, high resolution and simple structure, thus becoming a cost-effective and high-efficiency technology. Through numerical method, obtain the three dimensional model of cone-jet and emphasize the correlation of sediment diameter and PEO concentration. The theoretical graphics agree well with the experimental data, which can explain and provide some theoretical basis for the experiments.

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