Mechanical Engineering
NOTICE OF SEMINAR PRESENTATION
CANDIDATE: Johnson Babalola
DEGREE SOUGHT: MASc
DATE: 5/8/2026
TIME: 11:30am
PLACE: Room 1101 CEI
TITLE: Effect of Orifice Orientation in Perforated-Plate Grid-Generated Turbulence
Abstract
Perforated plates are commonly used to generate turbulence in wind-tunnel experiments, but the effect of orifice orientation on the developing turbulence field has received less attention. This study investigates turbulence produced by a perforated plate containing sharp-edged orifices with inclined walls, such that reversing the plate creates two opposite flow-passage orientations. These are referred to as the converging and diverging orientations. Velocity measurements were obtained downstream of the plate using hot-wire anemometry to examine how orifice orientation affects mean velocity, turbulence intensity, length scales, dissipation, and spectral behavior.
The results show that orifice orientation has a clear influence on the near-field turbulence structure. The diverging orientation produced higher turbulence levels, larger energy-containing structures, and stronger near-field dissipation, while the converging orientation showed a more gradual downstream development. Spectral and correlation analyses suggest that these orientation effects are most important at large scales and in the near field, whereas smaller-scale motions become less dependent on the initial orientation farther downstream. These findings show that orifice orientation can serve as a simple geometric parameter to control the structure and development of turbulence generated by perforated plates.