A Small-Scale Field Experiment on Random Froude-Krylov Force on a Rectangular Structure

2012 ◽  
Author(s):  
Felice Arena ◽  
Giovanni Malara
Keyword(s):  
Field Experiment ◽  
Wave Field ◽  
Time Domain ◽  
Time History ◽  
Wave Force ◽  
Floating Body ◽  
Small Scale ◽  
Ocean Engineering ◽  
Large Wave ◽  
Scale Field

This paper investigates random Froude-Krylov (FK) force on a rectangular structure. It is a key parameter in the design process of some maritime structures. Indeed, the exciting force on a large floating body is commonly determined by a contribution due to the incident wave field (FK) and by a contribution due to the diffraction of sea waves. The work is based on results of a small-scale field experiment at NOEL (Natural Ocean Engineering Laboratory) in Reggio Calabria, Italy. First, field experiment is described, with characteristics of the selected sea states. Then, FK forces are analytically derived in the context of linear random waves. Frequency spectrum of the FK force is derived and it is discussed the occurrence of zeros in frequency domain. Extreme FK forces are determined by Quasi-Determinism theory. The theory enables to derive the analytical expression of the FK force when a large wave (either a large crest height or a large crest-to-trough wave height) occurs at any given point of the wave field, in a fixed time instant. Time domain representation allows investigating the wave force and extreme wave pressure. It is shown that the wave force is highly width dependent in time domain. Further, time histories are not quasi-impulsive. This characteristic is well-rendered in large structures (large with respect to the dominant wave length), where the wave group crossing gives rise to a time history “protraction” in time domain. In the last part of the paper theoretical results are supplemented by comparison with experimental data.

A Small Scale Field Experiment for Hydrodynamic Coefficients of Morison’s Forces in Random Waves

2013 ◽  
Author(s):  
Felice Arena ◽  
Vincenzo Fiamma
Keyword(s):  
Field Experiments ◽  
Wave Spectrum ◽  
Wave Force ◽  
Small Scale ◽  
Random Wave ◽  
Wave Forces ◽  
Hydrodynamic Coefficients ◽  
Sea Waves ◽  
Ocean Engineering ◽  
Scale Field

The paper deals with wave forces on vertical and horizontal cylinders through the Morison’s equation. In particular, the hydrodynamics coefficients on cylinders are investigated by means of two small scale field experiments in the Natural Ocean Engineering Laboratory (NOEL) of the Mediterranea University of Reggio Calabria, by analyzing two stationary random processes of time: the measured wave force Fa(t), and the wave force calculated with the Morison equation Fc(t). The kinematics in the Morison’s equation is obtained with the theory of wind-generated waves from the directional wave spectrum obtained from measurements of surface waves. Starting from the measurements a new approach is proposed for the evaluation of the hydrodynamic coefficients of Morison’s forces for random sea waves. Finally, the distributions of the peaks of the random wave forces, Fa(t), and Fc(t), is achieved.

scholarly journals A SMALL-SCALE FIELD EXPERIMENT FOR THE VALIDATION OF A THEORY ON REFLECTION OF NONLINEAR SHORT-CRESTED WAVE GROUPS

2011 ◽  
Vol 1 (32) ◽  
pp. 58
Author(s):  
Alessandra Romolo ◽  
Felice Arena
Keyword(s):  
Field Experiment ◽  
Closed Form Solution ◽  
Form Solution ◽  
Wave Crest ◽  
Small Scale ◽  
Ocean Engineering ◽  
Wave Groups ◽  
Free Surface Displacement ◽  
Scale Field ◽  
The Impact

A closed-form solution of free surface displacement and velocity potential for nonlinear short-crested (3D) wave groups interacting with a reflective sea wall is presented. The theory is applied to investigate the fluctuation wave pressures when an exceptionally high crest or deep trough occurs on the reflective wall. A characteristic behaviour has been observed. Due to non-linearity, on one hand, great reduction of the highest crest and enhancement of the deepest troughs on wave pressures are realized; on the other hand, the profiles show always a strong asymmetry between the absolute maxima and the minima and sometimes the formation of characteristic humped wave pressures corresponding to the impact on the structure of the highest wave crest. All the theoretical results have been validated through a small-scale field experiment carried out at the Natural Ocean Engineering Laboratory (N.O.E.L., www.noel.unirc.it) of Reggio Calabria (Italy).

Crack Expansion and Fracturing Mode of Hydraulic Refracturing from Acoustic Emission Monitoring in a Small-Scale Field Experiment

2019 ◽  
Vol 52 (2) ◽  
pp. 543-553 ◽  
Author(s):  
Tsuyoshi Ishida ◽  
Wataru Fujito ◽  
Hiroto Yamashita ◽  
Makoto Naoi ◽  
Hirokazu Fuji ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Field Experiment ◽  
Small Scale ◽  
Acoustic Emission Monitoring ◽  
Emission Monitoring ◽  
Scale Field

Caisson breakwaters embodying an OWC with a small opening—Part II: A small-scale field experiment

2007 ◽  
Vol 34 (5-6) ◽  
pp. 820-841 ◽  
Author(s):  
Paolo Boccotti ◽  
Pasquale Filianoti ◽  
Vincenzo Fiamma ◽  
Felice Arena
Keyword(s):  
Field Experiment ◽  
Small Scale ◽  
Small Opening ◽  
Scale Field

SOIL REMINERALIZATION THROUGH THE ADDITION OF VOLCANIC ROCK MINING WASTE WITH SEWAGE SLUDGE FROM A DAIRY INDUSTRY: A SMALL-SCALE FIELD EXPERIMENT WITH BLACK OATS

2020 ◽  
Vol 7 (2020) (2) ◽  
pp. 1-9
Author(s):  
Amanda Silva ◽  
◽  
Adilson Dalmora ◽  
Beatriz Firpo ◽  
Rubens Kautzmann ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Field Experiment ◽  
Volcanic Rock ◽  
Dairy Industry ◽  
Mining Waste ◽  
Small Scale ◽  
X Ray ◽  
Scale Field ◽  
Rock Mining ◽  
Rock Dust

The present study focuses on the agronomic efficacy evaluation of volcanic rock mining waste and the sewage sludge from a dairy industry as a fertilizer for an acid soil, and to evaluate its nutrients and toxic potentially elements. The waste samples were collected from a volcanic rock mining and a dairy industry located in the southern region of Brazil. X-ray diffraction technique was employed to identify the mineralogical phases present in the rock dust. Rock and sludge major elements composition were analyzed after fusion along with LiBO2 followed by X-Ray Fluorescence. Toxic potentially elements content was measured according to United States Environmental Protection Agency 3050b method. The sludge and rock were applied to small-scale field experiment in which black oats was then sown. Four treatments were compared: (T1) 3,240 kg ha-1 of sewage sludge, (T2) 1,620 kg ha-1 of sewage sludge with 6,000 kg ha-1 of rock, (T3) 12,000 kg ha-1 of rock and control, which did not receive any type of input. Changes in soil properties and the nutritional status of the black oats were monitored after ninety days. The addition of the sludge combined with rock dust led to substantial increases in black oats leaves nutrient concentrations (mainly Ca, K, P and Zn) and in soil available K and P. In addition, the potentially toxic elements levels of both wastes are low and therefore the risks of environmental contamination are considerably reduced. Keywords: dairy industry sewage sludge; volcanic rock mining waste; natural soil fertilization.

Study on a Time Domain Prediction Method for Wave Force: Application for a Point-Absorber WEC

2018 ◽  
Author(s):  
Qiao Li ◽  
Motohiko Murai
Keyword(s):  
Time Domain ◽  
Wave Spectrum ◽  
Time Domain Analysis ◽  
Wave Force ◽  
Domain Analysis ◽  
Irregular Waves ◽  
Floating Body ◽  
Control Force ◽  
Electric Generator ◽  
The Time Domain

There are a lot of numerical analysis for solving hydrodynamic responses of a floating body in the time domain. Most of them can give a theoretical solution in given irregular waves. It means, however, that the solution can be obtained only if the accurate irregular waves represented by the wave spectrum should be given. As we consider the actual operation, we know it is difficult to detect the accurate irregular waves instantaneously as needed accuracy in the most of the time domain analysis for feed backing the control force to the system. This paper proposes a new method to predict the practical wave force from the displacement of waves at a floating body in time domain analysis almost instantaneously. The method, that can apply to predict forces in wave energy converter with linear electric generator, helps us to choose the control force for convert more electric power in irregular waves. We confirm the algorithm and examine its effectiveness.

Some Observations on the Movement of Pacific Salmon Fry through a Small Impounded Water Basin

1955 ◽  
Vol 12 (3) ◽  
pp. 362-368 ◽  
Author(s):  
D. MacKinnon ◽  
J. R. Brett
Keyword(s):  
Field Experiment ◽  
Pacific Salmon ◽  
Small Scale ◽  
Water Basin ◽  
Salmon Fry ◽  
Scale Field

A small-scale field experiment was conducted to investigate the migration of Pacific salmon fry through an impounded water basin, 2.4 acres in area. Pink, chum, coho, spring and sockeye fry were released at the upstream end. During nine days of operating a trap placed below the outlet dam, only pink and chum fry appeared. One-quarter of the total of these latter species moved through the impoundment and were recaptured. The migration of the fry was mainly confined to a period 11/2 hours after sunset to 11/2 hours before sunrise. The rate of migration of fry through the impoundment differed significantly from the movement of floats also released above the basin.

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