An Experimental Study of Annular Flows With Applications in Turbulent Film Lubrication

1967 ◽  
Vol 89 (3) ◽  
pp. 381-391 ◽  
Author(s):  
R. A. Burton ◽  
H. J. Carper
Keyword(s):  
Experimental Study ◽  
Shear Stress ◽  
Turbulent Flows ◽  
Large Scale ◽  
Journal Bearings ◽  
Major Influence ◽  
Plane Couette Flow ◽  
Pressure Distributions ◽  
Large Pressure ◽  
Film Lubrication

Experiments are reported on turbulent flows in air, in a large-scale bearing model of 6-ft dia, 2-ft length, 0.54-in. film thickness. Simulation of tilted pads, short journal bearings, and stepped pads is described. Pressure distributions are reported along with velocity and turbulence-intensity profiles. Wall shear stress is computed from the velocity profile measurements. The variations of these factors are compared with available data for plane Couette flow, wall law flow, and pressure flow in pipes, and the relationships among these are discussed. In addition, large pressure jumps at discontinuities are reported, and are shown to provide a major influence on the overall pressure distributions.

A Technique for the Measurement of Wall Shear Stress Based on Micro Fabricated Hot-Film Sensor

2013 ◽  
Author(s):  
Takuya Sawada ◽  
Osamu Terashima ◽  
Yasuhiko Sakai ◽  
Kouji Nagata ◽  
Mitsuhiro Shikida ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Turbulent Flows ◽  
Temporal Resolution ◽  
Large Scale ◽  
High Temporal Resolution ◽  
Film Sensor ◽  
Wall Shear ◽  
Hot Film ◽  
Hot Film Sensor

The objective of this study is to establish a technique for accurately measuring the wall shear stress in turbulent flows using a micro-fabricated hot-film sensor. Previously, we developed a hot-film sensor with a flexible polyimide-film substrate. This sensor can be attached to curved walls and be used in various situations. Furthermore, the sensor has a 20-μm-wide, heated thin metal film. However, the temporal resolution of this hot-film sensor is not very high owing to its substrate’s high heat capacity. Consequently, its performance is inadequate for measuring the wall shear stress “fluctuations” in turbulent flows. Therefore, we have developed another type of hot-film sensor in which the substrate is replaced with silicon, and a cavity has been introduced under the hot-film for reducing heat loss from the sensor and achieving high temporal resolution. Furthermore, for improving the sensor’s spatial resolution, the width of the hot-film is decreased to 10 μm. The structure of the hot-film’s pattern and the flow-detection mechanism are similar to those of the previous sensor. Experimental results show that new hot-film sensor works as expected and has better temporal resolution than the previous hot-film sensor. As future work, we will measure the wall shear stress for a turbulent wall-jet and discuss the relationship between a large-scale coherent vortex structure and wall shear stress based on data obtained using the new hot-film sensor.

An Experimental Study and Analysis of Turbulent Film Tilted Pad Bearings

1974 ◽  
Vol 96 (1) ◽  
pp. 168-173 ◽  
Author(s):  
R. A. Burton ◽  
H. J. Carper ◽  
Y. C. Hsu
Keyword(s):  
Experimental Study ◽  
Turbulent Flow ◽  
Large Scale ◽  
Velocity Profiles ◽  
Working Fluid ◽  
Pressure Distributions ◽  
Aspect Ratios

Velocity profiles and pressure distributions are reported for turbulent flow under tilted pads in a large scale bearing model (6-ft shaft size, with air as the working fluid). Results are extended analytically to other bearing sizes and aspect ratios.

Effectiveness of Small Onshore Seawall in Reducing Forces Induced by Tsunami Bore: Large Scale Experimental Study

2009 ◽  
Vol 4 (6) ◽  
pp. 382-390 ◽  
Author(s):  
Mary Elizabeth Oshnack ◽  
◽  
Francisco Aguíñiga ◽  
Daniel Cox ◽  
Rakesh Gupta ◽  
...  
Keyword(s):  
Experimental Study ◽  
Large Scale ◽  
Rigid Wall ◽  
Wave Profile ◽  
Small Individual ◽  
Wave Flume ◽  
Pressure Distributions ◽  
Field Reconnaissance ◽  
Wave Heights ◽  
Wire Resistance

Tsunami force and pressure distributions on a rigid wall fronted by a small seawall were determined experimentally in a large-scale wave flume. Six different seawall heights were examined, two of which were exposed to a range of solitary wave heights. The same experiment was done without a seawall for comparison. The measured wave profile contained incident offshore, incident broken, reflected broken, and transmitted wave heights measured using wire resistance and ultrasonic wave gauges. Small individual seawalls increased reflection of the incoming broken bore front and reduced force on the rigid landward wall. These findings agree well with published field reconnaissance on small seawalls in Thailand that showed a correlation between seawalls and reduced damage on landward structures.

scholarly journals Experimental Study by Optical and Statistical Methods of Large-Scale Velocity Fluctuations in the Flow Past a Cylinder

2019 ◽  
Vol 14 (3) ◽  
pp. 5-14
Author(s):  
S. S. Abdurakipov ◽  
K. G. Dobroselsky
Keyword(s):  
Experimental Study ◽  
Turbulent Flows ◽  
Large Scale ◽  
Particle Image ◽  
Velocity Fields ◽  
Velocity Fluctuations ◽  
Flow Past ◽  
Image Velocimetry ◽  
Flow Past A Cylinder ◽  
Proper Orthogonal

Using an optical method for measuring the velocity fields Particle Image Velocimetry (PIV) and a statistical method for analyzing coherent structures in turbulent flows Proper Orthogonal Decomposition (POD), an experimental study of the spatial structure of large-scale velocity fluctuations in the precavitational and cavitational flow past a circular cylinder with a Reynolds number of 280 000 was carried out.

Oscillating Turbulent Flow With or Without a Current About a Circular Cylinder

1997 ◽  
Vol 119 (2) ◽  
pp. 73-78 ◽  
Author(s):  
T. Sarpkaya ◽  
M. de Angelis ◽  
C. Hanson
Keyword(s):  
Turbulent Flows ◽  
Large Scale ◽  
Turbulence Models ◽  
Second Order ◽  
Time Dependent ◽  
Navier Stokes ◽  
Computational Accuracy ◽  
Pressure Distributions ◽  
Cfd Analyses ◽  
Predictor Corrector

CFD analyses of two benchmark, two-dimensional, sinusoidally oscillating, turbulent flows (one with zero mean and one with nonzero mean) at relatively large Reynolds and Keulegan-Carpenter numbers and relative current velocities, have been performed with CFD-ACE, a Favre-averaged Navier-Stokes (FANS) code. The primary purpose of the investigation was a critical assessment of the computational accuracy of time-dependent turbulent flows with large-scale unsteadiness. A number of turbulence models, including the standard k-ε, re-normalization group (RNG) based k-ε, and low-Reynolds number model have been employed. Among others, a second order in time, second order in space, second-level predictor-corrector finite-difference scheme has been used. The analysis produced the time-dependent in-line and transverse forces, the force coefficients, instantaneous velocity, vorticity, and pressure distributions, and streamlines. Representative results are compared with each other and with those obtained experimentally.

Experimental study of deformation processes in large-scale concrete structures under quasistatic loading

2020 ◽  
Vol 15 (5) ◽  
pp. 619-633
Author(s):  
Igor Shardakov ◽  
Irina Glot ◽  
Aleksey Shestakov ◽  
Roman Tsvetkov ◽  
Valeriy Yepin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Large Scale ◽  
Concrete Structures ◽  
Deformation Processes ◽  
Quasistatic Loading

The Departure from Equilibrium of Turbulent Boundary Layers

1968 ◽  
Vol 19 (1) ◽  
pp. 1-19 ◽  
Author(s):  
H. McDonald
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Kinetic Energy ◽  
Stress Distribution ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Two Dimensional ◽  
Pressure Distributions ◽  
Momentum Integral ◽  
State Examination

SummaryRecently two authors, Nash and Goldberg, have suggested, intuitively, that the rate at which the shear stress distribution in an incompressible, two-dimensional, turbulent boundary layer would return to its equilibrium value is directly proportional to the extent of the departure from the equilibrium state. Examination of the behaviour of the integral properties of the boundary layer supports this hypothesis. In the present paper a relationship similar to the suggestion of Nash and Goldberg is derived from the local balance of the kinetic energy of the turbulence. Coupling this simple derived relationship to the boundary layer momentum and moment-of-momentum integral equations results in quite accurate predictions of the behaviour of non-equilibrium turbulent boundary layers in arbitrary adverse (given) pressure distributions.

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