Drag law for monodisperse gas-solid systems using particle-resolved direct numerical simulation of flow past fixed assemblies of spheres

► Drag law for gas-solids flow using particle-resolved simulation of fixed spheres. ► Numerical method PUReIBM based on immersed boundary method with no forcing in fluid. ► PUReIBM is accurate, numerically convergent and consistent with two-fluid theory. ► New drag correlation is proposed that can be used in CFD simulation of fluidized beds.