The study of unsteady turbulent pipe flow is of value in providing information which can lead to an improved understanding of the phenomenon of turbulence. In such flows certain fundamental aspects of turbulent flow are exposed, which although present in steady turbulent flows, are not apparent under such conditions. In addition, due to the effect of inertia, some additional features of turbulence specific to transient flows can be present. Due to the technical difficulties involved, detailed measurements of turbulence in transient flow were not possible until quite recently. As a result of the availability of modern instrumentation and powerful computers, transient turbulent flow can now be readily investigated. Therefore, these flows are getting more attention for research studies [1]. The unsteady turbulence in the pipeline has been studied recently by Kataoka et al. [2], Maruyama et al. [3], Kurokawa and Morikawa [4], Lefebvre[5], and Greenblatt and Moss [6]. Velocity profiles were initially characterized by significant reduction of their wake component. The final phase of the acceleration was characterized by reconstitution of the wake, producing a velocity profile inflection and the generation of turbulence in that vicinity.

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