TY - JOUR
T1 - Low-frequency fluctuations in the near-wake region of a trapezoidal cylinder with low aspect ratio
AU - Miau, J. J.
AU - Wang, J. T.
AU - Chou, J. H.
AU - Wei, C. Y.
N1 - Funding Information:
This work was supported by National Science Council, Republic of China, under the contract number NSC 85-2622-E-006-018. The authors would also like to thank Mr. S.J. Wu for his help on wind tunnel calibration.
PY - 2003/4
Y1 - 2003/4
N2 - Base pressure signals obtained on a trapezoidal cylinder with an aspect ratio 4.7, at Reynolds numbers of the order of 104, were examined after being low-pass filtered at different cut-off frequencies. For the range of the Reynolds numbers studied, the integral time scales of the low-passed fluctuations versus the cut-off frequencies chosen was found to fall on a curve. Cross-correlation between the pressure fluctuations measured at the cylinder base and the velocity fluctuations detected in the near-wake region were examined with the signal traces low-passed at different cut-off frequencies. Accordingly, an optimal cut-off frequency was defined as the one corresponding to the highest correlation obtained. The integral time scale of the low-passed fluctuations in reference to the optimal cut-off frequency was found to be about two times the vortex-shedding period. The low-frequency variations measured appeared to be insensitive to the artificial tripping to the sidewall boundary layer, and exhibited a global behavior in a near-wake region.
AB - Base pressure signals obtained on a trapezoidal cylinder with an aspect ratio 4.7, at Reynolds numbers of the order of 104, were examined after being low-pass filtered at different cut-off frequencies. For the range of the Reynolds numbers studied, the integral time scales of the low-passed fluctuations versus the cut-off frequencies chosen was found to fall on a curve. Cross-correlation between the pressure fluctuations measured at the cylinder base and the velocity fluctuations detected in the near-wake region were examined with the signal traces low-passed at different cut-off frequencies. Accordingly, an optimal cut-off frequency was defined as the one corresponding to the highest correlation obtained. The integral time scale of the low-passed fluctuations in reference to the optimal cut-off frequency was found to be about two times the vortex-shedding period. The low-frequency variations measured appeared to be insensitive to the artificial tripping to the sidewall boundary layer, and exhibited a global behavior in a near-wake region.
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U2 - 10.1016/S0889-9746(03)00007-0
DO - 10.1016/S0889-9746(03)00007-0
M3 - Article
AN - SCOPUS:0042315058
SN - 0889-9746
VL - 17
SP - 701
EP - 715
JO - Journal of Fluids and Structures
JF - Journal of Fluids and Structures
IS - 5
ER -