محمود حشمتی

The global flexibility and local rigidity of corrugated pipes have made them a good candidate in many engineering applications such as aerospace, oil and gas industries, heat and cooling systems, compact heat exchangers, etc. In this study, dynamic responses of corrugated clamped-clamped pipes conveying fluid are investigated. The governing equations of the system are derived by using the Hamiltonian principle based on the Euler-Bernoulli beam hypothesis. Non-uniformity of the flow velocity profile is considered in the formulation for both laminar and turbulent fluid flow. So, the flow-profile-modification factor for laminar flow and space-dependent mean velocity for turbulent flow are proposed. For spatial discretization of these equations, the finite element method is used. The effects of several parameters including fluid velocity, the corrugation length, as well as corrugation amplitude on the stability of the pipe system are examined. Natural frequencies of the pipe in hydrostatic flow conditions and critical flow velocities are determined for a vast range of parameters. Numerical results show that the stability of the system is significantly affected by the corrugation length and amplitude.