Stability of horizontal and vertical pipes conveying fluid under the effects of additional point masses and springs

A cantilevered pipe conveying fluid is a non-conservative system and loses its stability for a sufficiently high flow velocity. When a fluid-conveying pipe is involved as a structural element in a mechanical system (e.g., in oil and gas industry), it is often preferred to maximize the critical flow velocity in the pipe. This study focuses on the possibility of increasing the critical flow velocity of horizontal and vertical pipes conveying fluid by considering one or more additional masses and/or springs at various locations along the pipe. Galerkin method is used to solve the equation of motion of the problem derived based on the linear theory of elasticity and a plug flow model assumption. The results of the present study are compared with those available in literature. The results show a possibility of increasing the critical fluid velocity for horizontal and vertical cantilevered pipes. It is observed that the critical flow velocity can be significantly increased by adding a spring and a point mass at specific positions depending on the mass ratio β of the system.