An overview of fluid-structure interaction experiments in single-elbow pipe systems

\u3cp\u3eFluid-structure interaction (FSI) in vibrating pipe systems is a phenomenon that finds its source, among other mechanisms, in unbalanced pressure forces acting on loose elbows. The subject has received considerable attention in theoretical research and practical engineering. Sixteen laboratory experiments carried out on liquid-filled single-elbow (L-shaped) pipe systems are reviewed herein. Eight frequency-domain and eight time-domain experiments are concisely described in the Appendices A and B. The purpose of nearly all experiments was to study FSI and demonstrate the influence of moving elbows on the dynamic behavior of liquid-filled piping systems. This historical review has an educational character with regard to the execution of laboratory experiments featuring FSI.\u3c/p\u3

Meshless computation of the coupled axial vibration of liquid-filled pipes

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Exact solution of linear hyperbolic four-equation system in axial liquid-pipe vibration

The so-called FSI four-equation model describes the axial vibration of liquid-filled pipes. Two equations for the liquid are coupled to two equations for the pipe, through terms proportional to the Poisson contraction ratio, and through mutual boundary conditions. Skalak (1955/1956ab) defined this basic model, which disregards friction and damping effects. The four equations can be solved with the method of characteristics (MOC). The standard approach is to cover the distance-time plane with equidistantly spaced grid-points and to time-march from a given initial state. This approach introduces error, because either numerical interpolations or wave speed adjustments are necessary. This paper presents a method of exact calculation in terms of a simple recursion. The method is valid for transient events only, because the calculation time grows exponentially with the duration of the event. The calculation time is proportional to the temporal and spatial resolution. The exact solutions are used to investigate the error due to numerical interpolations and wave speed adjustments, with emphasis on the latter

A Isebree Moens and DJ Korteweg: on the speed of propagation of waves in elastic tubes

The Moens-Korteweg formula for the speed of propagation of pressure waves dates back to 1878 and was used by Kries in haemodynamics and Frizell, Joukowsky, Allievi and others in waterhammer to calculate the pressure variations in unsteady pipe flows. This paper describes the life and work of Dutchmen Isebree Moens and Korteweg. Their doctoral dissertations (in Dutch) are partly translated, reviewed and compared with their key publications (in German). Korteweg gave Moens’ semi-empirical wavespeed a mathematical basis and he made the first contributions toward the study of fluid-structure interaction and unsteady friction. Their work is placed in historical context, in terms of both their predecessors and contemporaries, and also how it was subsequently built on by their successors in different disciplines