Experimental Method for the Measurements and Numerical Investigations of Force Generated on the Rotating Cylinder under Water Flow

The paper presents the experimental test setup and measurement method of hydrodynamic force generated on the rotating cylinder (rotor) under uniform flow including the free surface effect. The experimental test setup was a unique construction installed in the flume tank equipped with advanced flow generating and measuring systems. The test setup consisted of a bearing mounted platform with rotor drive and sensors measuring the hydrodynamic force. The low length to diameter ratio cylinders were selected as models of bow rotor rudders of a shallow draft river barge. The rotor dynamics was tested for the rotational speeds up to 550 rpm and water current velocity up to 0.85 m/s. The low aspect ratio of the cylinder and free surface effect had significant impacts on the phenomena influencing the generated hydrodynamic force. The effects of the rotor length to diameter ratio, rotational velocity to flow velocity ratio, and the Reynolds number on the lift force were analyzed. The validation of the computational model against experimental results is presented. The results show a similar trend of results for the simulation and experiment.

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CHF IN HIGH-PRESSURE REGIME FOR FORCED CONVECTION BOILING IN UNIFORMLY HEATED VERTICAL TUBES OF LOW LENGTH-TO-DIAMETER RATIO

Proceeding of International Heat Transfer Conference 7 ◽

10.1615/ihtc7.1100 ◽

1982 ◽

Cited By ~ 5

Author(s):

Yoshiro Katto ◽

S. Ashida

Keyword(s):

High Pressure ◽

Forced Convection ◽

Diameter Ratio ◽

Pressure Regime ◽

Vertical Tubes ◽

Length To Diameter Ratio

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Optimized growth of high length-to-diameter ratio Lu2O3 single crystal fibers by the LHPG method

CrystEngComm ◽

10.1039/d0ce01415j ◽

2021 ◽

Vol 23 (7) ◽

pp. 1657-1662

Author(s):

Na Zhang ◽

Yuqing Yin ◽

Jian Zhang ◽

Tao Wang ◽

Siyuan Wang ◽

...

Keyword(s):

Solid State ◽

Single Crystal ◽

High Power ◽

Diameter Ratio ◽

Solid State Lasers ◽

Crystal Fibers ◽

High Length ◽

Length To Diameter Ratio

Lu2O3 crystals have attracted intense attention due to their great potential in the field of high power solid-state lasers.

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EXPERIMENTAL STUDY ON FLAME PROPAGATION IN A STRAIGHT PIPE

Jurnal Teknologi ◽

10.11113/jt.v78.9568 ◽

2016 ◽

Vol 78 (8-3) ◽

Author(s):

Siti Zubaidah Sulaiman ◽

Rafiziana Md Kasmani ◽

A. Mustafa

Keyword(s):

Experimental Study ◽

Flame Propagation ◽

Experimental Work ◽

Diameter Ratio ◽

Straight Pipe ◽

Pipe Length ◽

Operating Condition ◽

Consistent Trend ◽

Length To Diameter Ratio

Flame propagation in a closed pipe with diameter 0.1 m and 5.1 m long, as well as length to diameter ratio (L/D) of 51, was studied experimentally. Hydrogen/air, acetylene/air and methane/air with stoichiometric concentration were used to observe the trend of flame propagation throughout the pipe. Experimental work was carried out at operating condition: pressure 1 atm and temperature 273 K. Results showed that all fuels are having a consistent trend of flame propagation in one-half of the total pipe length in which the acceleration is due to the piston-like effect. Beyond the point, fuel reactivity and tulip phenomenon were considered to lead the flame being quenched and decrease the overpressures drastically. The maximum overpressure for all fuels are approximately 1.5, 7, 8.5 barg for methane, hydrogen, and acetylene indicating that acetylene explosion is more severe.

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Roller Skewing Behavior in Roller Bearings

Journal of Lubrication Technology ◽

10.1115/1.3253206 ◽

1982 ◽

Vol 104 (3) ◽

pp. 311-320

Author(s):

L. J. Nypan

Keyword(s):

Diameter Ratio ◽

Radial Load ◽

Outer Race ◽

Roller Bearings ◽

Length To Diameter Ratio

Measurements of roller skewing of a 1.15 length to diameter ratio roller in 118 mm bore roller bearings of 0.18 and 0.21 mm (0.0073 and 0.0083 in.) clearance operating with a 4450 N (1000 lb) radial load at shaft speeds of 4000, 8000, and 12,000 rpm with outer race misalignment of 0, 0.5, and −0.5 deg are reported.

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The supersonic and low-speed flows past circular cylinders of finite length supported at one end

Journal of Fluid Mechanics ◽

10.1017/s0022112062000270 ◽

1962 ◽

Vol 12 (3) ◽

pp. 367-387 ◽

Cited By ~ 15

Author(s):

D. M. Sykes

Keyword(s):

Mach Number ◽

Finite Length ◽

Central Region ◽

Diameter Ratio ◽

Circular Cylinders ◽

Form Drag ◽

Drag Coefficients ◽

Low Speed ◽

Flow Past ◽

Length To Diameter Ratio

The flow past circular cylinders of finite length, supported at one end and lying with their axes perpendicular to a uniform stream, has been investigated in a supersonic stream at Mach number 1.96 and also in a low-speed stream. In both stream it was found that the flow past the cylinders could be divided into three regions: (a) a central region, (b) that near the free end of the cylinder, and (c) that near the supported end. The locations of the second and third regions were found to be almost independent of the cylinder length-to-diameter ratio, provided that this exceeded 4, while the flow within and the extent of the first region were dependent on this ratio. Form-drag coefficients determined in the central region in the supersonic flow were in close agreement with the values determined at the same Mach number by other workers. In the low-speed flow the local form-drag coefficients were dependent on length-to-diameter ratio and were always less than that of an infinite-length cylinder at the same Reynolds number.

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Numerical Analysis on the Electrical Performance of Microstructured Environmentally-Friendly Electrical Contact Material Ag/SnO2

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.419.355 ◽

2013 ◽

Vol 419 ◽

pp. 355-359

Author(s):

Lei Wang ◽

Wei Li Liu ◽

Le Sheng Chen

Keyword(s):

Numerical Simulation ◽

Electrical Contact ◽

Environmentally Friendly ◽

Weight Percent ◽

Diameter Ratio ◽

Electrical Performance ◽

Structural Parameter ◽

Contact Material ◽

Electrical Contact Material ◽

Length To Diameter Ratio

The paper analyzes the influence of structural parameters on the electrical performance of the microstructured environmentally-friendly electrical contact material Ag/SnO2 by using numerical simulation method.The numerical results show that the reisitivity of fiber-like electrical contact material Ag/SnO2 is significantly reduced compared with the resistivity of Ag/SnO2 adding reinforcing nanoparticles in the traditional way.So the fiber-like electrical contact material Ag/SnO2 exhibits higher conductivity in macro. On further analysis, we learn that the resistivity of fibrous electrical contact materials is related to weight percent of reinforced phase, and micro-structural parameter of length to diameter ratio. The resistivity increases as weight percent of reinforced phase increases,and decreases non-linearly with micro-structural parameter of length to diameter ratio increasing.This demonstrates that numerical simulation is one of effective methods for analysis of the electrical performance of the microstructured electrical contact material.

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A new method for calculating the sonic conductance of airflow through a short-tube orifice

Advances in Mechanical Engineering ◽

10.1177/1687814016687264 ◽

2017 ◽

Vol 9 (2) ◽

pp. 168781401668726 ◽

Cited By ~ 2

Author(s):

Fan Yang ◽

Gangyan Li ◽

Dawei Hu ◽

Toshiharu Kagawa

Keyword(s):

Flow Rate ◽

Critical Pressure ◽

Pressure Ratio ◽

Momentum Equation ◽

Diameter Ratio ◽

Test Method ◽

Theoretical Formula ◽

Engineering Applications ◽

Short Tube ◽

Length To Diameter Ratio

In this study, we proposed a method for calculating the sonic conductance of a short-tube orifice. First, we derived a formula for calculating the sonic conductance based on a continuity equation, a momentum equation and the definition of flow-rate characteristics. The flow-rate characteristics of different orifices were then measured using the upstream constant-pressure test method in ISO 6358. Based on these test data, the theoretical formula was simplified using the least squares fitting method, the accuracy of which was verified experimentally. Finally, the effects of the diameter ratio, the length-to-diameter ratio and the critical pressure ratio were analysed with reference to engineering applications, and a simplified formula was derived. We conclude that the influence of the diameter ratio is greater than that of the length-to-diameter ratio. When the length-to-diameter ratio is <5, its effect can be neglected. The critical pressure ratio has little effect on the sonic conductance of a short-tube orifice, and it can be set to 0.5 when calculating the sonic conductance in engineering applications. The formula proposed in this study is highly accurate with a mean error of <3%.

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