Environmental pollution, global warming, and depletion of fossil fuels compel radical changes in automotive engine technologies in directions that offer both the potential for achieving near-zero emissions of pollutants and greenhouse gases and a diversification of the transport fuel system away from its present exclusive dependence on fossil fuels. Hydrogen-fueled vehicles can be an environment-friendly alternative. Composite high-pressure tanks can be used for storage of hydrogen gas on board road vehicles. Durability and safety of the fuel tanks are the important concerns involved. In this paper a numerical model is developed for the analysis of the cyclic fast charging and discharging process of a high-pressure hydrogen gas tank to determine the effect on tank wall temperature. The flow is considered as compressible, viscous, unsteady and turbulent. Axisymmetric, time-dependent, Navier-Stokes equations were solved with the two-equation realizable k-ε turbulent model for turbulent momentum closure. Redlich-Kwong real gas equation was used for density computations. The numerical model is of relevance to the design of high-pressure tanks for durability and safety, primarily with regard to the wall configuration.