Gourma, MustaphaVerdin, Patrick G.2020-03-022020-03-022020-02-18Gourma M, Verdin PG. (2020) Nature and magnitude of operating forces in a horizontal bend conveying gas-liquid slug flows. Journal of Petroleum Science and Engineering, Volume 190, July 2020, Article number 1070620920-4105https://doi.org/10.1016/j.petrol.2020.107062http://dspace.lib.cranfield.ac.uk/handle/1826/15202Operating forces and magnitude of loads from gas-liquid slug flows exerted on a horizontally orientated 90o bend are investigated. The distributed forces are either Newtonian, associated with the fluids motion or Configurational, inherent to the internal distributions of the phases. The forces are derived through the conventional balances of mass and linear momentum arising from the volume of fluid (VOF) description of gas-liquid flows. The study uses the integral form of the momentum balance to estimate the operating forces budget. Invoking dynamical time scales separation discloses the connection of the Lamb vector (vortex-force) to the local time rate of momentum. An interesting outcome being an explicit expression for Favre-Reynolds stress that reveals the contribution of void fraction fluctuations in the redistribution of the stress across the interface. Numerical simulations are performed to determine the magnitude of Newtonian loads on bend using a segmented domain technique to represent the fully established slug flow regime. The time-dependent traces of the relevant flow variables such as liquid hold-up, flow rates and resultant forces on the bend are recorded and analysed. Compared to the isotropic component, the deviatoric stresses are shown to have a marginal contribution to the total forces. It is also shown that loading cycles on bends are much higher than slugging cycles; this is an important feature for the structural integrity assessment of pipelines with bends.enAttribution-NonCommercial-NoDerivatives 4.0 InternationalSlug flowSlug impactSingular interfaceLamb vectorFavre-Reynolds stressArticle