Numerical Simulation of the vortex shedding from two side-by-side square cylinders in gas-liquid two-phase flow

摘要

Considering the turbulence deduced by shearing stress and air bubble, and based on two-fluid model, gas-liquid two-phase flow around two square cylinders in side-by-side arrangement in vertical tube with different void fraction different spacing ratio is numerically simulated by using the finite volume method in this paper. It is found that the gap flow with the spacing ratio smaller than 2.0 is not only biased to one side, resulting in the formation of a narrower wake behind one cylinder and a wider wake behind the other, but also not-biased to neither of them; vortex shedding from the two cylinders with the spacing ratio larger than or equal to 2.0 is synchronized. But when the spacing ratio is equal to 2.0, In-phase mode is the predominant mode while anti-phase mode predominates when the spacing ratio is 2.5, 3.0, 5.0. In bias pattern, the cylinder with wide wake has smaller resistance, the cylinder with narrow wake has larger resistance, and the cylinders with middle wake have equality resistance. Meanwhile the spacing ratio has tremendous influence on pulsating lift, amplitude spectrum and so on. The volume of void fraction in the incident flow influence the vortex production, falling off & development heavily. When the volume of void fraction increases to 0.12, the stable vortex street does not produce.