scholarly journals Perceptual Scale Ratio of Frontal Axonometric Projection

1993 ◽  
Vol 27 (4) ◽  
pp. 25-28
Author(s):  
Shin-ichi MURAKAMI
Keyword(s):  
Scale Ratio ◽  
Perceptual Scale

Effects of Schmidt Number on Turbulent Mass Transfer Around a Rotating Circular Cylinder

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Dong-Hyeog Yoon ◽  
Kyung-Soo Yang ◽  
Klaus Bremhorst
Keyword(s):  
Mass Transfer ◽  
Circular Cylinder ◽  
Diffusion Layer ◽  
Time Scale ◽  
Schmidt Number ◽  
Concentration Field ◽  
Limiting Behavior ◽  
Rotating Circular Cylinder ◽  
Scale Ratio ◽  
Turbulent Mass Transfer

Characteristics of turbulent mass transfer around a rotating circular cylinder have been investigated by Direct Numerical Simulation. The concentration field was computed for three different cases of Schmidt number, Sc = 1, 10 and 100 at ReR* = 336. Our results confirm that the thickness of the Nernst diffusion layer decreases as Sc increases. Wall-limiting behavior within the diffusion layer was examined and compared with that of channel flow. Concentration fluctuation time scale was found to scale with r+2, while the time scale ratio nearly equals the Schmidt number throughout the diffusion layer. Scalar modeling closure constants based on gradient diffusion models were found to vary considerably within the diffusion layer. Results of an octant analysis show the significant role played by the ejection and sweep events just as is found for flat plate, channel, and pipe flow boundary layers. Turbulence budgets revealed a strong Sc dependence of turbulent scalar transport.

The structure of internal intermittency in turbulent flows at large Reynolds number: experiments on scale similarity

1973 ◽  
Vol 59 (3) ◽  
pp. 537-559 ◽  
Author(s):  
C. W. Van Atta ◽  
T. T. Yeh
Keyword(s):  
Reynolds Number ◽  
Probability Density ◽  
Streamwise Velocity ◽  
Statistical Characteristics ◽  
Large Reynolds Number ◽  
Higher Moments ◽  
Scale Similarity ◽  
Probability Densities ◽  
Scale Ratio ◽  
Velocity Derivative

Some of the statistical characteristics of the breakdown coefficient, defined as the ratio of averages over different spatial regions of positive variables characterizing the fine structure and internal intermittency in high Reynolds number turbulence, have been investigated using experimental data for the streamwise velocity derivative ∂u/∂tmeasured in an atmospheric boundary layer. The assumptions and predictions of the hypothesis of scale similarity developed by Novikov and by Gurvich & Yaglom do not adequately describe or predict the statistical characteristics of the breakdown coefficientqr,lof the square of the streamwise velocity derivative. Systematic variations in the measured probability densities and consistent variations in the measured moments show that the assumption that the probability density of the breakdown coefficient is a function only of the scale ratio is not satisfied. The small positive correlation between adjoint values ofqr,land measurements of higher moments indicate that the assumption that the probability densities for adjoint values ofqr,lare statistically independent is also not satisfied. The moments ofqr,ldo not have the simple power-law character that is a consequence of scale similarity.As the scale ratiol/rchanges, the probability density ofqr,levolves from a sharply peaked, highly negatively skewed density for large values of the scale ratio to a very symmetrical distribution when the scale ratio is equal to two, and then to a highly positively skewed density as the scale ratio approaches one. There is a considerable effect of heterogeneity on the values of the higher moments, and a small but measurable effect on the mean value. The moments are roughly symmetrical functions of the displacement of the shorter segment from the centre of the larger one, with a minimum value when the shorter segment is centrally located within the larger one.

scholarly journals The Effectiveness Of Reflexology Massage In Lowering The Blood Pressure In Elderly With Hypertension

2014 ◽  
Vol 1 (3) ◽  
pp. 200-204 ◽  
Author(s):  
Levi Tina Sari ◽  
Nevy Norma Renityas ◽  
Wahyu Wibisono
Keyword(s):  
Blood Pressure ◽  
Progressive Increase ◽  
Left Ventricular ◽  
Pharmacological Therapy ◽  
T Test ◽  
Lower Systolic Blood Pressure ◽  
Test Analysis ◽  
Ratio Data ◽  
Before And After ◽  
Scale Ratio

Elderly in the age of 60 or above is a natural process that can not be avoided where the life of man as a human being is limited by a rule of nature. As a result of the aging process, the blood vessels become stiff and affect the left ventricular wall reduce its elasticity, resulting in a progressive increase of blood pressure. The treatment of hypertension in addition to pharmacological therapy could also use non-pharmacological therapies such as reflexology massage.  Method: The research design used in this study was pre-experimental using one group pretest-posttest approach. In this research, the researchers measured blood pressure before and after the treatment (reflexology massage). The sample of this study was 20 respondents using purposive sampling. This research used statistical t-test analysis test, because it had a scale ratio data. Result : The result of t-test showed that p <0.0001, means that there was significantly different result before and after treatment with reflexology massage on the feet with a medium timber. Discussion : It is expected that people with hypertension do the feet reflexology massage in order to taking medication because can lower systolic blood pressure.

On the reverse swing of a cricket ball—modelling and measurements

2001 ◽  
Vol 215 (1) ◽  
pp. 45-55 ◽  
Author(s):  
A T Sayers
Keyword(s):  
Boundary Layer ◽  
Flow Visualization ◽  
Reynolds Numbers ◽  
Flow Conditions ◽  
Drag Forces ◽  
Cricket Ball ◽  
Direct Measurements ◽  
Scale Ratio ◽  
Lift And Drag ◽  
At Will

The phenomenon of reverse swing of the ball in a game of cricket is achieved by very few bowlers, and then only by those who seem able to bowl at speeds in excess of 85 mile/h. It also seems that reverse swing cannot be achieved at will. Rather, it is obtained perhaps by accident as much as by design, its inception being as much of a surprise to the bowler as to the batsman. This would suggest that the flow conditions pertaining to reverse swing are extremely marginal at best. This paper investigates the flow conditions required for reverse swing to occur and presents data describing the lift and drag on the ball. While some direct measurements are made on a cricket ball for comparison purposes, the flow over the ball is modelled through a 2.7:1 scale ratio sphere. This permitted relatively large lift and drag forces to be measured. The results define the range of Reynolds numbers and seam angles over which reverse swing will occur, as well as the corresponding forces on the cricket ball. Flow visualization is used to indicate the state of the boundary layer.

Evaluation of a Small and Fast Planing Boat’s Seakeeping Performance at the Design Stage

2015 ◽  
Author(s):  
Dong Jin Kim ◽  
Sun Young Kim
Keyword(s):  
Model Tests ◽  
Full Scale ◽  
Scale Model ◽  
Design Stage ◽  
Small Scale ◽  
Irregular Wave ◽  
Seakeeping Performance ◽  
Head Waves ◽  
Scale Ratio ◽  
Free Running

Seakeeping performance of a planing boat should be sufficiently considered and evaluated at the design stage for its safe running in rough seas. Model tests in seakeeping model basins are often performed to predict the performance of full-scale planing boats. But, there are many limitations of tank size and wave maker capacity, in particular, for fast small planing boats due to small scale ratio and high Froude numbers of their scale models. In this research, scale model tests are tried in various test conditions, and results are summarized and analyzed to predict a 3 ton-class fast small planing boats designed. In a long and narrow tank, towing tests for a bare hull model are performed with regular head waves and long crested irregular head waves. Motion RAOs are derived from irregular wave tests, and they are in good agreements with RAOs in regular waves. Next, model ships with one water-jet propulsion system are built, and free running model tests are performed in ocean basins. Wave conditions such as significant heights, modal periods, and directions are varied for the free running tests. Motion RMS values, and RAOs are obtained through statistical approaches. They are compared with the results in captive tests for the bare hull model, and are used to predict the full-scale boat performances.

The Effect of Distorted Scale Ratio on Harbor Resonance with Constant Water Depth

APAC 2019 ◽  
2019 ◽  
pp. 1263-1270
Author(s):  
Zhenjun Zheng ◽  
Xiaozhou Ma ◽  
Hongqiao Wu ◽  
Yujin Dong ◽  
Guohai Dong
Keyword(s):  
Water Depth ◽  
Harbor Resonance ◽  
Scale Ratio
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