Application of Ultrasound Time-Domain Correlation Method to Turbulent Pipe Flow at Low Reynolds Number

2002 ◽  
Vol 2002 (0) ◽  
pp. 407-408
Author(s):  
Gentaro YAMANAKA ◽  
Hiroshige KIKURA ◽  
Masanori ARITOMI
Keyword(s):  
Reynolds Number ◽  
Time Domain ◽  
Pipe Flow ◽  
Low Reynolds Number ◽  
Correlation Method ◽  
Turbulent Pipe Flow ◽  
Low Reynolds ◽  
Time Domain Correlation

Velocity Profile Measurement in Turbulent Pipe Flow Using Ultrasound Time-Domain Correlation Method

2002 ◽  
Author(s):  
Gentaro Yamanaka ◽  
Hiroshige Kikura ◽  
Masanori Aritomi
Keyword(s):  
Velocity Profile ◽  
Time Domain ◽  
Pipe Flow ◽  
Correlation Method ◽  
Turbulent Pipe Flow ◽  
Profile Measurement ◽  
Doppler Method ◽  
Velocity Profile Measurement ◽  
Pulse Doppler ◽  
Time Domain Correlation

This paper presents a velocity profile measurement technique using a ultrasound time-domain correlation method (UTDC). The system is based on the cross correlation between two consecutive echoes of ultrasonic pulses to detect the velocity. The UTDC has two advantages over a conventional ultrasound pulse Doppler method. First, the system has a higher time resolution than the pulse Doppler method. Second, the system does not have a limitation in maximum measurable velocity, which is limited by Nyquist’s sampling theorem. In this paper, the velocity profile measurement in turbulent pipe flow using the UTDC is performed.

Calculations of Wall Shear Stress in Harmonically Oscillated Turbulent Pipe Flow Using a Low-Reynolds-Number k-ε Model

1996 ◽  
Vol 118 (1) ◽  
pp. 189-194 ◽  
Author(s):  
J. O. Ismael ◽  
M. A. Cotton
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Pipe Flow ◽  
Low Reynolds Number ◽  
Turbulent Pipe Flow ◽  
Frequency Model ◽  
Wide Range ◽  
Wall Shear ◽  
Low Reynolds

The low-Reynolds-number k-ε turbulence model of Launder and Sharma is applied to the calculation of wall shear stress in spatially fully-developed turbulent pipe flow oscillated at small amplitudes. It is believed that the present study represents the first systematic evaluation of the turbulence closure under consideration over a wide range of frequency. Model results are well correlated in terms of the parameter ω+ = ωv/Uτ2 at high frequencies, whereas at low frequencies there is an additional Reynolds number dependence. Comparison is made with the experimental data of Finnicum and Hanratty.

Structure and dynamics of low Reynolds number turbulent pipe flow

2008 ◽  
Vol 367 (1888) ◽  
pp. 473-488 ◽  
Author(s):  
Andrew Duggleby ◽  
Kenneth S Ball ◽  
Markus Schwaenen
Keyword(s):  
Reynolds Number ◽  
Pipe Flow ◽  
Low Reynolds Number ◽  
Fourier Method ◽  
Phase Speed ◽  
Flow Fields ◽  
Turbulent Pipe Flow ◽  
Stress Generation ◽  
Basis Set ◽  
Low Reynolds

Using large-scale numerical calculations, we explore the proper orthogonal decomposition of low Reynolds number turbulent pipe flow, using both the translational invariant (Fourier) method and the method of snapshots. Each method has benefits and drawbacks, making the ‘best’ choice dependent on the purpose of the analysis. Owing to its construction, the Fourier method includes all the flow fields that are translational invariants of the simulated flow fields. Thus, the Fourier method converges to an estimate of the dimension of the chaotic attractor in less total simulation time than the method of snapshots. The converse is that for a given simulation, the method of snapshots yields a basis set that is more optimal because it does not include all of the translational invariants that were not a part of the simulation. Using the Fourier method yields smooth structures with definable subclasses based upon Fourier wavenumber pairs, and results in a new dynamical systems insight into turbulent pipe flow. These subclasses include a set of modes that propagate with a nearly constant phase speed, act together as a wave packet and transfer energy from streamwise rolls. It is these interactions that are responsible for bursting events and Reynolds stress generation. These structures and dynamics are similar to those found in turbulent channel flow. A comparison of structures and dynamics in turbulent pipe and channel flows is reported to emphasize the similarities and differences.

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