Parameter Identification of a Steel Catenary Riser Using Hilbert and Wavelet Transforms

2015 ◽  
Author(s):  
Lizeth Torres ◽  
Cristina Verde ◽  
Flavia Borges ◽  
Carlos Magluta ◽  
Ney Roitman
Keyword(s):  
Wavelet Transforms ◽  
The Other ◽  
Scale Model ◽  
Modal Parameters ◽  
Small Scale ◽  
Damping Factor ◽  
Steel Catenary Riser ◽  
Campos Basin ◽  
Mdof Systems ◽  
Small Scale Model

This article presents a methodology — for Multiple Degree of Freedom (MDOF) systems — to identify the modal parameters of a steel catenary riser (SCR) by employing both the Hilbert and the wavelet transforms. To validate the proposed approach, a set of experiments were performed in a small scale model of a real SCR that is installed in the P18 platform operating in Campos Basin, Brazil. During the experiments, the damping factor along the SCR was modified by adding viscoelastic sandwich layers on its structure. Each change was recorded with two accelerometers mounted at the bottom of the riser; one of them was set to get measurements in the catenary plane and the other one to get measurements out of the plane. Then, in order to obtain the impulse response of the structure — from which is possible to obtain the modal parameters — some hammer impacts were applied at locations close to these accelerometers.

Étude quantitative de l'érosion en aval des dissipateurs d'énergie type auge

2002 ◽  
Vol 29 (2) ◽  
pp. 201-210 ◽  
Author(s):  
A El Amri ◽  
J L Verrette
Keyword(s):  
Energy Dissipation ◽  
The Other ◽  
Scale Model ◽  
Small Scale ◽  
Other Hand ◽  
Energy Dissipators ◽  
The Impact ◽  
Small Scale Model ◽  
Impact Distance

Scour tests on downstream roller bucket energy dissipators have shown that, at the equilibrium, bed characteristics are mainly influenced by the discharge and by the height of the bucket lip. The discharge affects scour characteristics, without however modifying the shape of the bed. On the other hand, the height of the bucket lip simultaneously affects scour characteristics and the shape of the bed mainly in the vicinity of the structure. In the latter area, for larger values of the height of the bucket lip, one observes a deposition with a small depression on the top and, on the contrary, when the height of the bucket lip is small, one observes an erosion. Both the depth of scour and the thickness of the deposit increase proportionally to the height of the bucket lip. Values of the other bed characteristics decrease slightly with the height of the bucket lip to reach a minimum, then they increase for higher values of the height of the bucket lip. Comparison of bed characteristics at the equilibrium with the literature shows that theory overestimates the depth of the scour measured in the laboratory by an average of 68% for the three values of discharge, underestimates the impact distance by about 6% for low discharges, and overestimates it by 10% for the highest discharge.Key words: hydraulic energy dissipation, roller bucket, scour mecanism, scour, small-scale model.

scholarly journals DYNAMIC SIMILARITY OF TRANSPORT PHENOMENA

1980 ◽  
Vol 1 (17) ◽  
pp. 158
Author(s):  
M.S. Yalin ◽  
F. Gerritsen
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Physical Modelling ◽  
The Other ◽  
Scale Model ◽  
Small Scale ◽  
Separation Processes ◽  
Densimetric Froude Number ◽  
Ocean Environment ◽  
Small Scale Model

The discharges issued by OTEC plants, thermal power plants and other engineering devices, give rise to the transport of "foreign" properties and substances into the natural ocean environment. In order to predict the functioning of such structures and assess their environmental impact, physical modelling has already been utilized. Since the simultaneous fulfillment of both Reynolds and Froude criteria is impossible (in a conventional small scale model operating with the prototype fluid) in the models mentioned the transport phenomenon was reproduced on the basis of the densimetric Froude number (Fr) only, the influence of the Reynolds number (Re) being neglected. On the other hand, the identification of the scale of Fr (viz Apr) with unity can lead to substantial differences between the model and prototype values of Re. (Because AFr = 1 yields AR6 = Ax 3/2 where Xjt is the linear model scale.) Yet many of the pertinent aspects of a turbulent diffusion (energy dissipation, thickness of mixing zones, separation processes, etc.) are strongly dependent on Re, and therefore an appreciable distortion of Re (AJJ3/2

scholarly journals Diffraction and reflection of irregular waves in a harbor employing a spectral model

2009 ◽  
Vol 81 (4) ◽  
pp. 837-848 ◽  
Author(s):  
Nelson Violante-Carvalho ◽  
Rafael B. Paes-Leme ◽  
Domenico A. Accetta ◽  
Frederico Ostritz
Keyword(s):  
Coastal Waters ◽  
Wave Model ◽  
The Other ◽  
Irregular Waves ◽  
Scale Model ◽  
Small Scale ◽  
Swan Model ◽  
Relevant Role ◽  
Incident Waves ◽  
Small Scale Model

The SWAN wave model is widely used in coastal waters and the main focus of this work is on its application in a harbor. Its last released version - SWAN 40.51 - includes an approximation to compute diffraction, however, so far there are few published works that discuss this matter. The performance of the model is therefore investigated in a harbor where reflection and diffraction play a relevant role. To assess its estimates, a phase-resolving Boussinesq wave model is employed as well, together with measurements carried out at a small-scale model of the area behind the breakwater. For irregular, short-crested waves with broad directional spreading, the importance of diffraction is relatively small. On the other hand, reflection of the incident waves is significant, increasing the energy inside the harbor. Nevertheless, the SWAN model does not achieve convergence when it is set to compute diffraction and reflection simultaneously. It is concluded that, for situations typically encountered in harbors, with irregular waves near reflective obstacles, the model should be set without the diffraction option.

Wave Energy Hyperbaric Device for Electricity Production

2007 ◽  
Author(s):  
Segen F. Estefen ◽  
Paulo Roberto da Costa ◽  
Eliab Ricarte ◽  
Marcelo M. Pinheiro
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Experimental Results ◽  
Electricity Production ◽  
Scale Model ◽  
Small Scale ◽  
Regular Waves ◽  
Hyperbaric Chamber ◽  
Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

Staged-Air Ratio Optimization for a New Down-Fired Technology within a Cold Small-Scale Model of a 350 MWeUtility Boiler

2011 ◽  
Vol 25 (4) ◽  
pp. 1485-1496 ◽  
Author(s):  
Min Kuang ◽  
Zhengqi Li ◽  
Pengfei Yang ◽  
Jinzhao Jia ◽  
Qunyi Zhu
Keyword(s):  
Scale Model ◽  
Small Scale ◽  
Ratio Optimization ◽  
Small Scale Model

scholarly journals Monitoring deformation of small scale model tunnels under load testing

Survey Review ◽  
2014 ◽  
Vol 46 (339) ◽  
pp. 417-425 ◽  
Author(s):  
H-M. Chen ◽  
M. Smith ◽  
H-S. Yu ◽  
N. Kokkas
Keyword(s):  
Scale Model ◽  
Small Scale ◽  
Load Testing ◽  
Small Scale Model

A small-scale model of factor VIII and factor IX fractionation from plasma

1989 ◽  
Vol 10 (4) ◽  
pp. 279-286 ◽  
Author(s):  
Peter Feldman ◽  
Lowell Winkelman ◽  
Helen Evans ◽  
Martin Pinnell ◽  
Fiona Murdoch ◽  
...  
Keyword(s):  
Factor Viii ◽  
Factor Ix ◽  
Scale Model ◽  
Small Scale ◽  
Small Scale Model

A Small Scale Model for Seismic Imaging Systems

1972 ◽  
pp. 195-213 ◽  
Author(s):  
M. G. Maginness ◽  
G. B. Cook ◽  
L. G. Higgens
Keyword(s):  
Seismic Imaging ◽  
Imaging Systems ◽  
Scale Model ◽  
Small Scale ◽  
Small Scale Model
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