This paper reports viscous compressible aerodynamics analysis of two-dimensional cascades (arrays of aerofoils). The study elucidates the effect of cascade parameters such as solidity, δ, and angle of attack, α on the interference between blades. Understanding the interference behaviour is important in the performance analysis of air turbines such as Wells turbine commonly used in oscillating water column (OWC) - wave energy converter (WEC) system. The present analysis shows that isolated two-dimensional lift coefficient modified by interference factors, Kο, based on inviscid flow theory is acceptable for low solidity cascades, i.e. δ > 0.5, Kο, and that stall occurs at lower angle of attack in cascade compared to isolated aerofoil. When δ > 0.5, Kο is shown to depend on both α and δ especially in the post-stall flow. The result suggests that interference factors that is applicable for wide range of flow conditions as in Wells turbines should also include the α effect in the modifier.