The wake flow structure of an open-slit V gutter

Abstract

This work experimentally investigates the near-wake flow structure behind an open-slit V gutter at airflow speeds between 1 m/s and 20 m/s. With the aid of Schlieren photography and a Dantec three-beam, two-component laser-Doppler anemometry system, the phenomena of vortex shedding and flow recirculation behind the flameholder are well investigated. The results indicate that the interaction between the flow penetrating through the open slit and the shear layer results in an asymmetric wake flow structure. The lower shear layer develops more stably and smoothly than the upper shear layer. Besides, the vortex formation along the lower wing is delayed and at a location farther downstream. The size of the entire recirculation zone is enlarged, and its center shifts toward one of the two wings. Measurements of wake pressure distribution show that the open-slit V gutter generates higher back pressure and thus induces less drag force than the regular V gutter. Moreover, the maximum values of the pressure fluctuation of the wake flow behind the open-slit V gutter reduce 27% and 9%, for the upper side and the lower side, respectively, much lower than those of the regular V gutter. In general, the application of mass bleed from the open-slit V gutter favors both the flame-holding mechanism and the suppression of the flow-induced oscillation.