Abstract
In order to investigate the sustaining mechanism of the large-scale streamwise vortical structures in a turbulent Couette flow, a vorticity-probe consisted of 4-X type hotwire has been developed. The probe performance was estimated by measuring the fluctuating velocity and vorticity components in turbulent Poiseuille flow and comparing them with DNS and/or LDV measurements. Contributions to Dω^^-_1/Dt from various terms of ω^^-_1 transport equation in Poiseuille flow and Couette flow are estimated using data obtained from vorticity-probe. In Poiseuille flow the total of these terms weaken the streamwise vortex, while the one in Couette flow has no such tendency. These results are consistent with the decaying or sustaining properties of the streamwise vortex in Poiseuille or Couette flow.
