Comparative studies of hot-wire techniques for moderate intensity flows

Abstract EN

Methods employing hot wire anemometer techniques in obtaining quantitative turbulence information in turbulent flows are numerous.

These techniques, however, were tested in different flow geometries under different operating conditions.

It is difficult to decide on a technique preference unless the different techniques are tested under similar operating conditions and flow geometry.

It is the main objective of this study to compare the single-wire, .r-wire, and triple-wire measurement techniques under the same operating conditions.

Measurements of mean velocity and Reynolds stress components were conducted at seven different axial locations downstream of the jet exit plane using the single-wire, .r-wire , and triple-wire techniques.

A computer controlled three-dimensional traverse mechanism in conjunction with a data acquisition software developed for turbulent flow measurements and analysis were utilized.

The results showed that the three hot wire techniques gave similar results for the mean velocity components U, V, Wand the Reynolds stress components uv, UW, vw and u', This agreement, however, was not apparent when comparing the normal stresses v2 and w2 , especially for the singlewire technique.

A very close agreement was achieved when the normalized mean axial velocity, U/Uc and the normalized turbulence intensity u' IU, were compared with the data published in the literature.

This resulted in a good confidence of the accuracy of the measurement techniques used.