Our study is focused on the singing risers phenomenon which is encountered in corrugated channels under flow. Internal corrugations are responsible for flow instabilities that synchronize with longitudinal acoustic modes of the channel giving powerful pure tones. Experiments are performed in a specifically designed facility. Numerical simulations of the flow based on a lattice Boltzmann method (LBM) are faced to the experimental results. They aimed at investigating the ability of a LBM based simulation to predict the aeroacoustics of corrugated channels. Acoustic modes and turbulence in the corrugated channel are quite well predicted except the sound pressure levels that need better description of the acoustic boundary conditions.

The intense whistling of corrugated pipe under flow is related to a coherence between the dynamics of structures developing in the shear layer over cavities and acoustic eigenmodes of the pipe. In order to highlight the coupling between aerodynamics and acoustics, three measurement systems with complementary characteristics in terms of space and time resolutions are synchronized. The simultaneity of the measurements of velocity and acoustic pressure provided by five local probes, as two hot-wires and three microphones, with the velocity fields measured by PIV in the same flow region is used to estimate the velocity fields at frequencies compatible with the space-time characterization of the acoustic sources. The linear stochastic estimation (LSE) is performed to reconstruct these high frequency velocity fields. Two rectangular corrugated pipes with different corrugation geometry are investigated. Thanks to the LSE velocity field reconstruction, the contribution of the flow structures, both jet flapping and vortex shedding, to acoustic level is highlighted. V

Since the early 2000, Flow Induced Pulsations (FLIP) has been more and more encountered on platforms. This phenomenon generates high acoustic pressure pulsations that may cause noises up to one hundred and ten dB and significant fatigue stress levels in small piping either at topside or subsea equipment. The source of the phenomenon is inside of the flexible pipe but FLIP has no effect on it. Nevertheless, in case of FLIP experience companies may have to reduce their flow rate. Therefore, FLIP must be understood in order for the companies to avoid this constraint. In this frame, a FLIP test was performed with protagonists who are involved in the understanding of this phenomenon. The test was done in 2016 at CESAME Poitiers (France) in an eighteen meter-long and six-inch flexible pipe on an air open loop. The prototype was fully instrumented and pressures up to forty bars were tested and mass flow rates up to 6 kg.s−1 to reproduce the FLIP phenomenon. The test setup and signals analysis are presented in this paper. Moreover, FLIP onset velocities and frequencies are compared with TechnipFMC models. As a conclusion of this paper pressure influence for the six-inch tested on the FLIP initiation will be presented.