Coastal Engineering

Sorensen, Robert M.

doi:10.1007/978-1-4757-2665-7_1

Cited by 39 publications

(67 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…e wave height H, wave length L, and wave period Tare the major wave parameters [33,34]. Moreover, di erent environmental conditions were characterized by using water depth d which is applicable to determine the wave theories [35].…”

Section: Wave Forcesmentioning

confidence: 99%

Evaluation of Offshore Wind Turbine Tower Dynamics with Numerical Analysis

Dağlı

Tuskan

Gökkuş

2018

Advances in Civil Engineering

View full text Add to dashboard Cite

A dynamic behaviour of a cylindirical wind tower with variable cross section is investigated under environmental and earthquake forces.e ground acceleration term is represented by a simple cosine function to investigate both normal and parallel components of the earthquake motions located near ground surface. e function of earthquake force is simplified to apply Rayleigh's energy method. Wind forces acting on above the water level and wave forces acting on below this level are utilized in computations considering earthquake effect for entire structure. e wind force is divided into two groups: the force acting on the tower and the forces acting on the rotor nacelle assembly (RNA). e drag and the inertial wave forces are calculated with water particle velocities and accelerations due to linear wave theory. e resulting hydrodynamic wave force on the tower in an unsteady viscous flow is determined using the Morison equation. e displacement function of the physical system in which dynamic analysis is performed by Rayleigh's energy method is obtained by the single degree of freedom (SDOF) model. e equation of motion is solved by the fourth-order Runge-Kutta method. e two-way FSI (fluid-structure interaction) technique was used to determine the accuracy of the numerical analysis. e results of computational fluid dynamics and structural mechanics are coupled in FSI analysis by using ANSYS software. Time-varying lateral displacements and the first natural frequency values which are obtained from Rayleigh's energy method and FSI technique are compared. e results are presented by graphs. It is observed from these graphs that the Rayleigh model can be an alternative way at the prelimanary stage of the structural analysis with acceptable accuracy.

show abstract

Section: Wave Forcesmentioning

confidence: 99%

Evaluation of Offshore Wind Turbine Tower Dynamics with Numerical Analysis

Dağlı

Tuskan

Gökkuş

2018

Advances in Civil Engineering

View full text Add to dashboard Cite

show abstract

“…The channel has 250 meter length, 5 meter width, and a mean water level depth H which is equal to 5 meters. Irregular wave conditions in the tests were described by a Joint North Sea Wave Project (JONSWAP) frequency spectrum (Hasselman et al, 1973) with significant wave height H s =1.5 m, peak period f p =5.9 s, and the generated random waves with a long crest (Sorensen, 1993). Induced forces recorded by sensors which had been installed on the cylinder at 5 height levels.…”

Section: Characteristics Of the Measured Experimental Datamentioning

confidence: 99%

Experimental investigation of TARMAX model for modeling of hydrodynamic forces on cylinder-like structures

Lotfollahi-Yaghin

Mojtahedi

Ettefagh

et al. 2011

J. Marine. Sci. Appl.

View full text Add to dashboard Cite

A new approach that models lift and drag hydrodynamic force signals operating over cylindrical structures was developed and validated. This approach is based on stochastic auto regressive moving average with exogenous (ARMAX) input and its time-varying form, TARMAX. Model structure selection and parameter estimation were discussed while considering the validation stage. In this paper, the cylindrical structure was considered as a dynamic system with an incoming water wave and resulting forces as the input and outputs, respectively. The experimental data, used in this study, were collected from a full-scale rough vertical cylinder at the Delft Hydraulics Laboratory. The practicality of the proposed method and also its efficiency in structural modeling were demonstrated through applying two hydrodynamic force components. For this purpose, an ARMAX model is first used to capture the dynamics of the process, relating in-line forces provided by water waves; secondly, the TARMAX model was applied to modeling and analysis of the lift forces on the cylinder. The evaluation of the lift force by the TARMAX model shows the model is successful in modeling the force from the surface elevation.

show abstract

“…(1) based on the linear wave theory (where k is the wave number, σ a wave angular frequency, z the depth at which the particle velocity is calculated, h the water depth, H the wave height and T the wave period). In this equation, σ is a wave angular frequency that is equal to 2π/T (DEAN; DALRYMPLE, 2000;SORENSEN, 2006).…”

Section: Mooringmentioning

confidence: 99%

Two experimental fish aggregating systems (fads) in the Aegean sea: their design and application

Özgül¹,

Lök²,

Düzbastılar³

2011

Braz. j. oceanogr.

View full text Add to dashboard Cite

A B S T R A C TTwo steel spar buoys were constructed and moored in 50 and 100 m deep of water in the Aegean Sea to support recreational fisheries. The first FAD was deployed at coordinates 38°01´48´´N 26°58´02´´E and at a distance of 3 nautical miles from the shoreline. The other FAD was moored at 1.1 nautical miles from the shoreline at coordinates 38°03´11´´N; 26°59´01´´E. An anchor (1.2x1.2x0.8 m3) weighing approximate 2.76 metric ton, made of reinforced concrete, was used to hold a FAD weighing approximate 1.5 metric ton. Hardware and connections of FADs, ropes, mooring calculation and anchor design were made. The interaction between the forces of wave and current and FADs in those waters was investigated. In the experiment, all forces (drag force, buoyancy force etc.) acting on FADs were calculated. It is proposed that the construction of the FADs should take the following design criteria into consideration: wave and current, forces related to the FADs, deployment depth, mooring hardware and ropes. This knowledge provides an important reference for stakeholders performing projects aiming to increase the performance and service life FADs.

show abstract

Coastal Engineering

Cited by 39 publications

References 2 publications

Evaluation of Offshore Wind Turbine Tower Dynamics with Numerical Analysis

Evaluation of Offshore Wind Turbine Tower Dynamics with Numerical Analysis

Experimental investigation of TARMAX model for modeling of hydrodynamic forces on cylinder-like structures

Two experimental fish aggregating systems (fads) in the Aegean sea: their design and application

Contact Info

Product

Resources

About