Radial Flow Between Axisymmetric Nonparallel Plates of Small Slope

1988 ◽  
Vol 110 (2) ◽  
pp. 342-346
Author(s):  
R. F. Gans ◽  
A. G. Johnson ◽  
S. B. Malanoski
Keyword(s):  
Excellent Agreement ◽  
Mass Flux ◽  
Radial Flow ◽  
Central Pressure ◽  
Axially Symmetric ◽  
Air Mass ◽  
Bearing Load ◽  
Dramatic Difference ◽  
Theory And Experiment

We have measured the separation and central pressure of a slightly concave axially symmetric pressurized bearing as a function of lubricant (air) mass flux and bearing load. We find that a mean face slope of 1.6 × 10−3 makes a dramatic difference in the behavior of the bearing, reducing the central pressure by more than a factor of two and eliminating the need for overpressures to start the system. We have also explored the behavior of the system analytically and find excellent agreement between theory and experiment.

Diode-Laser Sensor for Air-Mass Flux 2: Non-Uniform Flow Modeling and Aeroengine Tests

AIAA Journal ◽  
2007 ◽  
Vol 45 (9) ◽  
pp. 2213-2223 ◽  
Author(s):  
Kent H. Lyle ◽  
Jay B. Jeffries ◽  
Ronald K. Hanson ◽  
Michael Winter
Keyword(s):  
Diode Laser ◽  
Mass Flux ◽  
Uniform Flow ◽  
Laser Sensor ◽  
Flow Modeling ◽  
Air Mass ◽  
Diode Laser Sensor

Computation of linear elastic properties from microtomographic images: Methodology and agreement between theory and experiment

Geophysics ◽  
2002 ◽  
Vol 67 (5) ◽  
pp. 1396-1405 ◽  
Author(s):  
Christoph H. Arns ◽  
Mark A. Knackstedt ◽  
W. Val Pinczewski ◽  
Edward J. Garboczi
Keyword(s):  
Elastic Properties ◽  
Excellent Agreement ◽  
Fontainebleau Sandstone ◽  
Linear Elastic ◽  
Numerical Predictions ◽  
Wide Range ◽  
Digitized Images ◽  
Water Saturated ◽  
Dry Water ◽  
Theory And Experiment

Elastic property‐porosity relationships are derived directly from microtomographic images. This is illustrated for a suite of four samples of Fontainebleau sandstone with porosities ranging from 7.5% to 22%. A finite‐element method is used to derive the elastic properties of digitized images. By estimating and minimizing several sources of numerical error, very accurate predictions of properties are derived in excellent agreement with experimental measurements over a wide range of the porosity. We consider the elastic properties of the digitized images under dry, water‐saturated, and oil‐saturated conditions. The observed change in the elastic properties due to fluid substitution is in excellent agreement with the exact Gassmann's equations. This shows both the accuracy and the feasibility of combining microtomographic images with elastic calculations to accurately predict petrophysical properties of individual rock morphologies. We compare the numerical predictions to various empirical, effective medium and rigorous approximations used to relate the elastic properties of rocks to porosity under different saturation conditions.

Axially Symmetric Radial Flow of Rigid/Linear-Hardening Materials

1979 ◽  
Vol 46 (2) ◽  
pp. 322-328 ◽  
Author(s):  
D. Durban
Keyword(s):  
Radial Flow ◽  
Closed Form Solution ◽  
Wire Drawing ◽  
Form Solution ◽  
Flow Rule ◽  
Axially Symmetric ◽  
Linear Hardening ◽  
Stress Components ◽  
Von Mises ◽  
Good Agreement

A closed-form solution has been discovered for axially symmetric radial flow of rigid/linear-hardening materials. It is assumed that the materials obey the von Mises flow rule and that the flow field is in steady state. Explicit expressions for the stress components and the radial velocity are given. The applicability of the solution to wire drawing or extrusion is discussed. Some approximate formulas are derived and shown to be in good agreement, within their range of validity, with experimental results for drawing.

scholarly journals Characteristics of vertical air motion in isolated convective clouds

2016 ◽  
Vol 16 (15) ◽  
pp. 10159-10173 ◽  
Author(s):  
Jing Yang ◽  
Zhien Wang ◽  
Andrew J. Heymsfield ◽  
Jeffrey R. French
Keyword(s):  
Vertical Velocity ◽  
Mass Flux ◽  
Convective Precipitation ◽  
Small Scale ◽  
High Plains ◽  
Air Mass ◽  
Convective Clouds ◽  
Field Campaigns ◽  
Air Motion

Abstract. The vertical velocity and air mass flux in isolated convective clouds are statistically analyzed using aircraft in situ data collected from three field campaigns: High-Plains Cumulus (HiCu) conducted over the midlatitude High Plains, COnvective Precipitation Experiment (COPE) conducted in a midlatitude coastal area, and Ice in Clouds Experiment-Tropical (ICE-T) conducted over a tropical ocean. The results show that small-scale updrafts and downdrafts (<  500 m in diameter) are frequently observed in the three field campaigns, and they make important contributions to the total air mass flux. The probability density functions (PDFs) and profiles of the observed vertical velocity are provided. The PDFs are exponentially distributed. The updrafts generally strengthen with height. Relatively strong updrafts (>  20 m s−1) were sampled in COPE and ICE-T. The observed downdrafts are stronger in HiCu and COPE than in ICE-T. The PDFs of the air mass flux are exponentially distributed as well. The observed maximum air mass flux in updrafts is of the order 104 kg m−1 s−1. The observed air mass flux in the downdrafts is typically a few times smaller in magnitude than that in the updrafts. Since this study only deals with isolated convective clouds, and there are many limitations and sampling issues in aircraft in situ measurements, more observations are needed to better explore the vertical air motion in convective clouds.

Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets

1996 ◽  
Author(s):  
Michael Miller ◽  
William Kessler ◽  
Mark Allen
Keyword(s):  
Diode Laser ◽  
Mass Flux ◽  
Air Mass ◽  
Flux Sensor

scholarly journals Characterizing model errors in chemical transport modeling of methane: Impact of model resolution in versions v9-02 of GEOS-Chem and v35j of its adjoint model

2019 ◽  
Author(s):  
Ilya Stanevich ◽  
Dylan B. A. Jones ◽  
Kimberly Strong ◽  
Robert J. Parker ◽  
Hartmut Boesch ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Mass Flux ◽  
General Circulation ◽  
Lower Troposphere ◽  
Vertical Transport ◽  
Total Carbon ◽  
Fourier Transform Spectrometer ◽  
High Latitudes ◽  
Model Errors ◽  
Air Mass

Abstract. The GEOS-Chem simulation of atmospheric CH4 was evaluated against observations from the Thermal And Near infrared Sensor for carbon Observations Fourier Transform Spectrometer (TANSO-FTS) on the Greenhouse gases Observing SATellite (GOSAT), the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), and the Total Carbon Column Observing Network (TCCON). We focused on the model simulations at the 4° × 5° and 2° × 2.5° horizontal resolutions for the period of February–May 2010. Compared to the GOSAT, TCCON, and ACE-FTS data, we found that the 2° × 2.5° model produced a better simulation of CH4, with smaller biases and a higher correlation to the independent data. We found large resolution-dependent differences such as a latitude-dependent XCH4 bias, with higher columns abundances of CH4 at high latitudes and lower abundances at low latitudes at the 4° × 5° resolution than at 2° × 2.5°. We also found large differences in CH4 column abundances between the two resolutions over major source regions such as China. These differences resulted in up to 30 % differences in inferred regional CH4 emission estimates from the two model resolutions. We performed several experiments using 222Rn, 7Be and CH4 to determine the origins of the resolution-dependent errors. The results suggested that the major source of the latitude-dependent errors is excessive mixing in the upper troposphere and lower stratosphere, including mixing at the edge of the polar vortex, that is pronounced at the 4° × 5° resolution. At the coarser resolution, there is weakened vertical transport in the troposphere at mid- to high latitudes due to the loss of sub-grid tracer eddy mass flux in the storm track regions. We also identified reduced vertical transport at the coarser resolution. The vertical air mass fluxes are calculated in the model from the degraded coarse-resolution wind fields and the model does not conserve the air mass flux between model resolutions; as a result, the low resolution does not fully capture the vertical transport. This produces significant localized discrepancies, such as much greater CH4 abundances in the lower troposphere over China at 4° × 5° than at 2° × 2.5°. Although we found that the CH4 simulation is significantly better at 2° × 2.5° than at 4° × 5°, biases may still be present at 2° × 2.5° resolution. Their importance, particularly, in regards to inverse modeling of CH4 emissions, should be evaluated in future studies using on-line transport in the native general circulation model as a benchmark simulation.

scholarly journals Characteristics of Vertical Air Motion in Convective Clouds

2016 ◽  
Author(s):  
Jing Yang ◽  
Zhien Wang ◽  
Andrew J. Heymsfield ◽  
Jeffrey R. French
Keyword(s):  
Vertical Velocity ◽  
Mass Flux ◽  
Convective Precipitation ◽  
Small Scale ◽  
High Plains ◽  
Tropical Ocean ◽  
Air Mass ◽  
Convective Clouds ◽  
In Situ Data ◽  
Field Campaigns

Abstract. The vertical velocity and air mass flux in convective clouds are statistically analyzed using aircraft in-situ data collected from three field campaigns: High-Plains Cumulus (HiCu) conducted over the mid-latitude High Plains, COnvective Precipitation Experiment (COPE) conducted in a mid-latitude coastal area, and Ice in Clouds Experiment-Tropical (ICE-T), conducted over a tropical ocean. This study yields the following results. (1) Small-scale updrafts and downdrafts (< 500 m in diameter) are frequently observed in the three field campaigns, and they make important contributions to the total air mass flux. (2) The probability density functions (PDFs) of the vertical velocity are exponentially distributed. For updrafts, the PDFs of the vertical velocity are broader in ICE-T and COPE than in HiCu; for downdrafts, the PDFs of the vertical velocity are broader in HiCu and COPE than in ICE-T. (3) Vertical velocity profiles show that updrafts are stronger in ICE-T and COPE than in HiCu, and downdrafts are stronger in HiCu and COPE than in ICE-T. (4) The PDFs of the air mass flux are exponentially distributed as well. The maximum air mass flux in updrafts is of the order 104 kg m−1 s−1. The air mass flux in the downdrafts is typically a few times smaller in magnitude than that in the updrafts.

Diode-Laser Sensor for Air-Mass Flux 1: Design and Wind Tunnel Validation

AIAA Journal ◽  
2007 ◽  
Vol 45 (9) ◽  
pp. 2204-2212 ◽  
Author(s):  
Kent H. Lyle ◽  
Jay B. Jeffries ◽  
Ronald K. Hanson
Keyword(s):  
Wind Tunnel ◽  
Diode Laser ◽  
Mass Flux ◽  
Laser Sensor ◽  
Air Mass ◽  
Diode Laser Sensor
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