Hydrodynamic and thermal entrance region assessment of turbulent flow through a circular tube with a tight-fit twisted tape insert, considering multifarious operating conditions and pitch ratios

•Evaluation of Hydrodynamic and thermal flow developed in turbulent and laminar flow.•Distinguishing features of developing and fully-developed flow in Twisted-tape flow.•Correlations for Nu, friction factor, hydrodynamic, and thermal entrance length.•Novel essential criteria to assess a fully-development state in a twist tape flow.