THE VELOCITY-FIELD OF THE TURBULENT VERY NEAR WAKE OF A CIRCULAR-CYLINDER

Hot-wire measurements were conducted in the very near wake (x/d less t han or equal to 10) of a circular cylinder at a Reynolds number based on cylinder diameter, Re-d of 3900. Measurements of the streamwise vel ocity component with the use of single sensor hot-wire probes were fou nd to be inaccurate for such flowfields where high flow angles are pre sent. An X-array probe provided detailed streamwise and lateral veloci ty component statistics. Frequency spectra of these two velocity compo nents are also presented. Measurements with a 4-sensor hot-wire probe confirmed that the very near wake region is dominantly two-dimensional , thus validating the accuracy of the present X-array data.