Riser Modal Identification in CFD and Full-Scale Experiments
نویسندگان
چکیده
A systematic methodology is presented to obtain the vortex induced vibrational modes of a riser, based on data from CFD coupled to a long beam under tension and placed in sheared cross-flow; two profiles were tested: (a) linear, and (b) exponential. The modes we estimate are in fact nonlinear equilibria between the flow-induced excitation forces and the structural dynamics and are characterized by varying amplitude and phase along the span; these are complex modes, mixtures of traveling and standing waves. Simplifying procedures to represent the VIV response in terms of a few clusters of modes have been applied successfully, reducing substantially the data needed to represent the VIV response. c © 2006 Elsevier Ltd. All rights reserved.
منابع مشابه
A novel reduced order model for vortex induced vibrations of long flexible cylinders
In this manuscript the development of a reduced order model for the analysis of long flexible cylinders in an offshore environment is proposed. In particular the focus is on the modelling of the vortex induced vibrations (VIV) and the aim is the development of a model capable of capturing both the in-line and cross-flow oscillations. The reduced order model is identified starting from the resul...
متن کاملFull-Scale Resistance Prediction in Finite Waters – A Study Using CFD Simulations, Model Test Experiments and Sea Trial Measurements
The development of large medium-speed catamarans aims increasing economic viability and reducing the possible negative influence on the environment of fast sea transportation. These vessels are likely to operate at hump speed where wave-making can be the dominating component of the total resistance. Shallow water may considerably amplify the wave-making and hence the overall drag force. Computa...
متن کاملPrediction of gasoline yield in a fluid catalytic cracking (FCC) riser using k-epsilon turbulence and 4-lump kinetic models: A computational fluid dynamics (CFD) approach
FCC riser; Computational fluid dynamics (CFD); Cracking reaction kinetics; Hydrodynamics; 4-Lump kinetic model; k-Epsilon turbulence model Abstract Fluid catalytic cracking (FCC) is an essential process for the conversion of gas oil to gasoline. This study is an effort to model the phenomenon numerically using commercial computational fluid dynamics (CFD) software, heavy density catalyst and 4-...
متن کاملIdentification of Nonlinear Modal Interactions in a Beam-Mass-Spring-Damper System based on Mono-Frequency Vibration Response
In this paper, nonlinear modal interactions caused by one-to-three internal resonance in a beam-mass-spring-damper system are investigated based on nonlinear system identification. For this purpose, the equations governing the transverse vibrations of the beam and mass are analyzed via the multiple scale method and the vibration response of the system under primary resonance is extracted. Then,...
متن کاملDevelopment of a draft-tube airlift bioreactor for Botryococcus braunii with an optimized inner structure using computational fluid dynamics.
The key parameters of the inner structure of a cylindrical airlift bioreactor, including the ratio of the cross-section area of the downcomer to the cross-section area of the riser, clearance from the upper edge of the draft tube to the water level, and clearance from the low edge of the draft tube to the bottom of the reactor, significantly affected the biomass production of Botryococcus braun...
متن کامل