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Hyoeun shim(심효은),Changhoon Lee(이창훈) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11
The modulation of homogeneous and isotropic turbulence by microbubbles is investigated by using direct numerical simulation at Taylor scale reynolds number Re<SUB>λ</SUB> = 62. Within the different classes involved in the two-phase flows, the focus of present work is on the modification of turbulent flow by bubbles, immersed dilutely in the flow. The trajectory of bubbles is calculated by using Lagrangian tracking and the motion of bubbles is assumed to be governed by the added mass, gravity, drag and lift force. The effect of microbubbles on the flow is incorporated by applying the point-force approximation. The obtained results show that momentum transfer from bubbles to the flow behaves non-uniformly across the dissipation spectrum. The spectrum exhibits the enhancement of energy at high wavenumbers, while the converse is observed at low wavenumbers. This in turn is consistent with observations of Mazzitelli et al(2003) and van denBerg et al(2006).