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Experiments in Fluids

, Volume 16, Issue 6, pp 368–374 | Cite as

Sensitivity of three-segment electrodiffusion probes to eddy shedding

  • V. Sobolik
  • J. Tihon
  • J. Pauli
  • U. Onken
Originals

Abstract

The influence of eddy shedding on the instantaneous readings of a three-segment cylindrical electrodiffusion velocity probe was investigated in an immersed jet with a very low turbulence intensity, σ = 1.2%. The velocity fluctuations measured by the three-segment probe were smaller than 2.6%, and the maximum error in the flow angle estimation was 2∘. Vortices with the Strouhal frequency were detected by a simple electrodiffusion probe placed downstream of the three-segment probe, but no peaks with this frequency were found on the frequency spectra of the three-segment probe. From the probe response to a stepwise change of the polarization voltage the characteristic times of the transient process were estimated.

Keywords

Vortex Characteristic Time Frequency Spectrum Turbulence Intensity Maximum Error 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

a

parameter in Eq. (1) [A sb m-b]

A

amplitude gain

b

parameter in Eq. (1)

c

parameter in Eq. (3) [A s−1/2]

d

probe diameter [m]

f

frequency [s−1]

fs

recording frequency [s−1]

G

power spectrum

Ik

relative current through k-th segment, Eq. (2)

i

total current [A]

ik

current through k-th segment [A]

N

number of data samples

Re

Reynolds number, \(Re = vd\rho /\mu \)

Sr

Strouhal number, \(Sr = fd/v\)

t

time [s]

t0

characteristic transient time [s]

v

jet velocity [m s-1]

v

time mean value of velocity [m s-1]

vx, y

velocity components measured by probe [m s-1]

var

variance, var\(\left( x \right) = \sum\limits_{i = 1}^N {\left( {x_1 - x^ - } \right)^2 /N} \)

μ

dynamic viscosity [Pa s]

ϱ

density [kg m-3]

σ

relative deviation, \(\sigma (x) = 100.(\sqrt {\operatorname{var} (x)/\bar x} \) [%]

Θ

flow angle, see Fig. 1

Ω

dimensionless frequency

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Copyright information

© Springer Verlag 1994

Authors and Affiliations

  • V. Sobolik
    • 1
  • J. Tihon
    • 1
  • J. Pauli
    • 2
  • U. Onken
    • 2
  1. 1.Academy of Sciences of the Czech RepublicInstitute of Chemical Process FundamentalsPraha 6Czech Republic
  2. 2.Department of Technical Chemistry BUniversity of DortmundDortmundGermany

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