Fluctuating forces caused by internal two-phase flow on bends and tees

The time-dependent forces resulting from a two-phase air–water mixture flowing in an elbow and a tee are measured. Their magnitudes as well as their spectral contents are analyzed. Comparison is made with previous experimental results on similar systems. For practical applications a dimensionless form is proposed to relate the characteristics of these forces to the parameters defining the flow and the geometry of the piping. Using a momentum balance we show that these forces are correlated with local measurements of the void fraction in the flow.