Effect of large-scale structures on wall shear stress fluctuations in pipe flow

2020 ◽  
Vol 5 (10) ◽  
Author(s):  
Tong Tong ◽  
Kovid Bhatt ◽  
Tatsuya Tsuneyoshi ◽  
Yoshiyuki Tsuji
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pipe Flow ◽  
Large Scale ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Wall Shear

Very Large-Scale Structures and Their Effects on the Wall Shear-Stress Fluctuations in a Turbulent Channel Flow up to Reτ=640

2004 ◽  
Vol 126 (5) ◽  
pp. 835-843 ◽  
Author(s):  
Hiroyuki Abe ◽  
Hiroshi Kawamura ◽  
Haecheon Choi
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
High Reynolds Number ◽  
Large Scale ◽  
Turbulent Channel Flow ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Wall Shear ◽  
High Reynolds

Direct numerical simulation of a fully developed turbulent channel flow has been carried out at three Reynolds numbers, 180, 395, and 640, based on the friction velocity and the channel half width, in order to investigate very large-scale structures and their effects on the wall shear-stress fluctuations. It is shown that very large-scale structures exist in the outer layer and that they certainly contribute to inner layer structures at high Reynolds number. Moreover, it is revealed that very large-scale structures exist even in the wall shear-stress fluctuations at high Reynolds number, which are essentially associated with the very large-scale structures in the outer layer.

Preston-Static Tubes for the Measurement of Wall Shear Stress

1994 ◽  
Vol 116 (3) ◽  
pp. 645-649 ◽  
Author(s):  
Josef Daniel Ackerman ◽  
Louis Wong ◽  
C. Ross Ethier ◽  
D. Grant Allen ◽  
Jan K. Spelt
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Convenient Method ◽  
Pipe Flow ◽  
Total Pressure ◽  
Static Pressure ◽  
Shear Stresses ◽  
Streamline Curvature ◽  
Syringe Needle ◽  
Wall Shear

We present a Preston tube device that combines both total and static pressure readings for the measurement of wall shear stress. As such, the device facilitates the measurement of wall shear stress under conditions where there is streamline curvature and/or over surfaces on which it is difficult to either manufacture an array of static-pressure taps or to position a single tap. Our “Preston-static” device is easily and conveniently constructed from commercially available regular and side-bored syringe needles. The pressure difference between the total pressure measured in the regular syringe needle and the static pressure measured in the side-bored one is used to determine the wall shear stress. Wall shear stresses measured in pipe flow were consistent with independently determined values and values obtained using a conventional Preston tube. These results indicate that Preston-static tubes provide a reliable and convenient method of measuring wall shear stress.

Estimation of gas wall shear stress in horizontal stratified gas-liquid pipe flow

AIChE Journal ◽  
1996 ◽  
Vol 42 (8) ◽  
pp. 2369-2373 ◽  
Author(s):  
Charles H. Newton ◽  
Masud Behnia
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pipe Flow ◽  
Wall Shear

scholarly journals On The Measurement of Wall Shear Stress due to Oscillatory Pipe Flow

1994 ◽  
Vol 38 ◽  
pp. 475-480
Author(s):  
Shoichi KUSHITA ◽  
Hiroshi YASUKAWA ◽  
Masakazu UI
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pipe Flow ◽  
Wall Shear

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.

scholarly journals The evolution of large-scale motions in turbulent pipe flow

2015 ◽  
Vol 779 ◽  
pp. 701-715 ◽  
Author(s):  
Leo H. O. Hellström ◽  
Bharathram Ganapathisubramani ◽  
Alexander J. Smits
Keyword(s):  
Pipe Flow ◽  
Large Scale ◽  
Complex Structure ◽  
Turbulent Pipe Flow ◽  
Large Scale Structures ◽  
Large Structures ◽  
Scale Structures ◽  
The Cross ◽  
Spatio Temporal ◽  
Temporal Extent

A dual-plane snapshot proper orthogonal decomposition (POD) analysis of turbulent pipe flow at a Reynolds number of 104 000 is presented. The high-speed particle image velocimetry data were simultaneously acquired in two planes, a cross-stream plane (2D–3C) and a streamwise plane (2D–2C) on the pipe centreline. The cross-stream plane analysis revealed large structures with a spatio-temporal extent of $1{-}2R$, where $R$ is the pipe radius. The temporal evolution of these large-scale structures is examined using the time-shifted correlation of the cross-stream snapshot POD coefficients, identifying the low-energy intermediate modes responsible for the transition between the large-scale modes. By conditionally averaging based on the occurrence/intensity of a given cross-stream snapshot POD mode, a complex structure consisting of wall-attached and -detached large-scale structures is shown to be associated with the most energetic modes. There is a pseudo-alignment of these large structures, which together create structures with a spatio-temporal extent of approximately $6R$, which appears to explain the formation of the very-large-scale motions previously observed in pipe flow.

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