A study by a double-refraction method of the development of turbulence in a long circular tube

A streaming double-refraction method was employed to examine the flow in a long glass tube of a very weak solution of benzopurpurin in water. Two kinds of turbulent entry were used: with one, laminar flow at a Reynolds number of about 1900 was observed at cross-sections more than 120 diameters from the entry; with the other the corresponding distance was 90 diameters. The nature of the breakdown of laminar flow at a cross-section was found to depend upon the kind of entry and upon the distance of the cross-section from the inlet. The development of complete turbulence at various cross-sections was also investigated.