Comparisons of two-phase boundary layer and channel turbulence laden by inertial particles at moderate Reynolds number

The particle behavior and turbulent modulation of wall-bounded turbulent flow are analyzed by comparing a new simulation of channel turbulence with older simulation of spatially developing turbulent boundary layer at almost identical friction Reynolds number and laden particles with identical inertia and bulk volume fraction. It is found that particle locally accumulate in the wake region of the external boundary layer flow due to more pronounced turbulent/nonturbulent interface effect. Therefore, the particle-turbulence interaction in the outer layer of boundary layer results in stronger turbulent modulation than that in particle-laden channel. This influence not only makes the outer-layer structures more different but may penetrate to the near-wall region of wall turbulence, generating opposite modulation of turbulent mean velocity of the two flows. However, the modulation in second-order statistics and turbulent structures by the presence of inertial particles are qualitatively similar below the logarithmic layer. The similarities/dissimilarities are further explained by comparing the average stress, the turbulent kinetic energy budget and uniform momentum zones/quiescent core.