NEAR-WAKE CHARACTERISTICS OF VARIOUS V-SHAPED BLUFF-BODIES

Mechanism of vortex-shedding and turbulent flow features of the near-wake flow behind regular/irregular v-shaped bluff bodies are experimentally investigated at various airflow speeds between 10-60 m/s. With the aid of schlieren photography and a three-beam, two-component backward-scattering LDA system, the phenomena of vortex shedding and flow recirculation behind the flameholder are well illustrated. Results show Strouhal numbers, based on vortex shedding frequencies, being independent of gutter shape and within a range of 0.23-0.25. A similar flow structure of flow exists among near wake flows of v-gutters with different span angles. Increase of Reynolds number monotonically reduces the size of the recirculation zone. Variation in attack angle only slightly changes mean flow features, but enhances normalized Reynolds shear stresses in the near-wake.