Investigation of Particle Loading on the Turbulent Flow Over a Deep Cavity

Abstract

Turbulent particle-laden flows are of interest due to their presence in many industrial and natural flows. The effect that the particles have on the turbulence of the fluid is referred to as turbulence modulation. Experimental data is lacking at Reynolds numbers (Re) greater than 100,000, and at dense loadings (ΦV > 1%). In this work, turbulent particle-laden flow over a deep cavity with an aspect ratio of 1, was studied at Re of 11,500 and 115,000, and particle loadings of 0%, 1%, 3%, and 5% by weight/volume using neutrally buoyant particles (solid-phase specific gravity = 1). Super absorbent particles were used to create an index-matched environment with water as the working fluid. Data were acquired using two-dimensional planar particle image velocimetry along the center span of the geometry. Mean and root-mean-square velocities were calculated for the fluid phase. The flow structures were identified and located using the gamma criteria. The results showed that the particle loading changed the locations of the recirculation regions within the cavity. The mean velocities were nominally unaffected by loading for a respective Re case. Prior literature suggested that the particles would attenuate the turbulence, however, the current data showed no single trend. Turbulence modulation of the flow was found to be sensitive to the Re and location within the flow field. The changes in the turbulence appeared to be primarily due to the differences in the location of the flow structures.