ESTIMATION OF SHEAR-INDUCED LIFT FORCE IN LAMINAR AND TURBULENT FLOWS

摘要

The goal of the present study is to ensure that direct numerical simulations (DNS) coupled with interface tracking methods (ITM) can be used to estimate interfacial forces. The lift force on a single bubble is quantified through DNS in various conditions. Specifically, for low shear flows (2.0 s~(-1)) the effect of the wall presence is analyzed, and for high shear flows the effect of turbulence is studied. A proportional-integral-derivative (PID) based controller was implemented into the finite-element based, multiphase flow solver (PHASTA) to control the bubble position. This capability allowed utilization of a force balance on the bubble to determine lift and drag forces. The high shear laminar and turbulent (110, 236 s~(-1)) cases proved to be a more challenging control problem than the low shear laminar cases.