## 1 Introduction
[16] experimentally investigated the formation of slug flow through particle image velocimetry in a fully turbulent air-water two-phase flow in horizontal piping at a constant gas and liquid superficial velocity. They analysed the slug flow characteristics and developed a correlation to predict slug translational velocity on the basis of the maximum local velocity in the slug tail. [PERSON] et al. [17] investigated the effect of flow rate and physical geometry in CO\({}_{2}\)-water two-phase flow in a developed flow regime. They found that at a relatively low gas superficial velocity, bubble flow is highly likely to occur relative to slug flow. [PERSON] et al. [18] numerically investigated the slug characteristics in air-water two-phase flow in horizontal piping by using STAR-CCM+ software and validated the numerical results against those in the literature [13]. [PERSON] [18] also utilised his validated numerical model to simulate the two-phase flow of air-oil with specific grade to explore the effect of changing the fluids' physical properties on slug characteristics. On the basis of the limited data set utilised in their study, they concluded that liquid physical properties have a significant effect on slug characteristics. [PERSON] [19] performed experimental and numerical investigation to study the effect of varying water and air velocity on the slug behaviour and characteristics in Plexiglass pipe. [PERSON] used STAR-CCM+ software in his numerical investigation. [PERSON] et al. [20] numerically investigated the pressure gradient, slug liquid holdup and slug frequency of oil-gas two-phase flow in horizontal piping. They developed a correlation to predict slug liquid holdup and slug frequency as a function of gas superficial velocity. However, they reported a limitation in which the proposed correlations are only applicable to fluids with similar properties. [PERSON] et al. [21] numerically investigated the slug liquid holdup and transition velocity for oil-gas oil vapor in horizontal piping and investigated their effect on varying gas superficial velocities. [PERSON] et al. [22] statistically analysed the results from their experimental investigation on highly viscous oil-air slug flow in horizontal piping. They concluded that liquid physical properties greatly influence slug characteristics, and that slug length decreases as liquid viscosity increases. [PERSON] et al. [23; 24] experimentally investigated the effect of varying liquid viscosities on slug length and slug translational velocity by utilising two gamma densitometers with fast sampling frequencies. They utilised dimensional anal ysis and established an empirical correlation to predict slug length and slug translational velocity. [PERSON] et al. [25] investigated the effect of changing the operating conditions and physical properties of two-phase flow on pressure drop through the implementation of a multilayer perceptron artificial neural network model. However, their findings are used to validate the results of the developed algorithm. [PERSON] et al. [26] constructed an experimental facility and utilised nonintrusive instrumentation technique for the measurement of the Taylor bubbles, liquid slug' translational velocity, slug frequency and liquid slug lengths of an air-silicon oil two-phase flow in a pipe flow rig. They concluded that slug translational velocity is significantly dependent on the superficial velocity of the mixture. As the gas superficial velocity increases, the Taylor bubbles and liquid slug lengths increase. As the liquid superficial velocity increases, the slug frequency increases. Several researchers have investigated the cascading effect of slug characteristics on the deformation of the mechanical properties of piping by utilising conventional analytical and experimental methods [27; 28; 29] in which slugs are geometrically idealised as a moving load in pipes with a fixed length, velocity and frequency. However, the slug characteristics were predefined as an input to the model. [PERSON] et al.