Developing flows and developed flows

This paper puts emphasis on the problem of the developing flows in the circular tube under oscillatory conditions. According to the Navier-Stokes' equations and using the method of Bessel function of imaginary argument, a system of formulas is obtained. Comparing the formulas obtained in this paper with Atabek's formulas, it may be seen that the former is simpler and more convenient. When both the formulas obtained in this paper and Atabek's formulas are reduced to the representation of developed flows, both of them are consistent. Numerical calculation results show that the computed results obtained in this paper are rather consistent with both Atabek's computed results and the experimental results.