TY - CONF

T1 - Statistical properties of a coherent structure function for homogeneous isotropic turbulence and turbulent channel flows

AU - Kobayashi, Hiromichi

AU - Tominaga, Yasuhiro

AU - Kubota, Taisuke

AU - Tanahashi, Mamoru

AU - Miyauchi, Toshio

N1 - Funding Information:
Young Scientists KAKENHI (B), Grant No. 20760119, and HK gratefully acknowledges its support.
Funding Information:
HK is deeply grateful to Professor F. Hamba for teaching how to produce the initial velocity field of the HIT. This work was supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan, Grant-in-Aid for Figure 10: Conditional pdf of FCS by the Q values; (top) at Reλ = 60.1, Qmin = −1.40 × 104,Qmax = 2.42 × 104, ∆xq = 3.82 × 102; (bottom) for an initial velocity field, Qmin=−1.30×105,Qmax=2.04×105,∆xq=3.34×103.
Publisher Copyright:
© 2009 TSFP4 Symposium. All Rights Reserved.

PY - 2009

Y1 - 2009

N2 - Statistical properties of a coherent structure function FCS are investigated using DNS data for homogeneous isotropic turbulence and turbulent channel flows. The function FCS is defined as the second invariant Q of a velocity gradient tensor normalized by the magnitude E of the velocity gradient tensor. In homogeneous isotropic turbulence, the probability density function (pdf) of FCS shows good agreement at different Reynolds number. The volume fraction of positive Q and the average of FCS converge to a certain value at high Reynolds number. For the turbulent channel flows, the pdf of FCS at different Reynolds number coincides very well at the distance from the wall in wall units. The profiles of the conditional average of positive and negative Q, the volume fraction, and the near-wall FCS 2 are in good agreement at different Reynolds number and those profiles are given as a function of the distance from the wall in wall units.

AB - Statistical properties of a coherent structure function FCS are investigated using DNS data for homogeneous isotropic turbulence and turbulent channel flows. The function FCS is defined as the second invariant Q of a velocity gradient tensor normalized by the magnitude E of the velocity gradient tensor. In homogeneous isotropic turbulence, the probability density function (pdf) of FCS shows good agreement at different Reynolds number. The volume fraction of positive Q and the average of FCS converge to a certain value at high Reynolds number. For the turbulent channel flows, the pdf of FCS at different Reynolds number coincides very well at the distance from the wall in wall units. The profiles of the conditional average of positive and negative Q, the volume fraction, and the near-wall FCS 2 are in good agreement at different Reynolds number and those profiles are given as a function of the distance from the wall in wall units.

UR - http://www.scopus.com/inward/record.url?scp=85048391381&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85048391381&partnerID=8YFLogxK

M3 - Paper

AN - SCOPUS:85048391381

SP - 335

EP - 340

T2 - 6th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2009

Y2 - 22 June 2009 through 24 June 2009

ER -