Wave-Current Loading on a Vertical Slender Cylinder by Two Different Numerical Models

2006 ◽  
Author(s):  
M. H. Zaman ◽  
R. E. Baddour
Keyword(s):  
Numerical Models ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Finite Depth ◽  
Offshore Structure ◽  
Current Field ◽  
Oblique Wave ◽  
Waves And Currents ◽  
Current Loading

The study of the effects resulting from the interaction of a combined wave-current field with any ocean structure is important for the design and performance evaluation of that structure. The prudent computation of forces exerted by waves and currents is an essential task in the study of the stability of an offshore structure. A study on the loading of an oblique wave and a current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in Zaman and Baddour (2004). The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. In this work a 2D version of the above 3D model called here Model-I has been used for the numerical computations presented in this paper. The second model denoted model-II in the present paper is based on Euler equations. This model is formulated through the vertical integration of the continuity equation and the equations of motions, Zaman et al (1997). A semi-implicit numerical technique is employed for the numerical solution. In the present paper comparisons are made between the results obtained from the 2D version of the above models in finite depth. Both models are then compared with some relevant experimental data. Morison et al equation (1950) is deployed for the load computations in all cases.

Combined Loading of a Wave and Surface Current on a Fixed Vertical Slender Cylinder

2005 ◽  
Author(s):  
M. H. Zaman ◽  
R. E. Baddour
Keyword(s):  
Three Dimensional ◽  
Vertical Cylinder ◽  
Surface Current ◽  
Finite Depth ◽  
Combined Loading ◽  
Current Analysis ◽  
Current Field ◽  
3D Flow ◽  
Uniform Current ◽  
Uniform Currents

A study on the loading of an oblique surface wave and a surface current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in the present paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. The surface current considered in this report, is assumed uniform and acting over a layer of fluid that extends from the free surface to a specified finite depth. Prior work assumes that uniform currents existed over the total depth of the fluid domain. In this paper we extend the approach considered in Zaman and Baddour (2004) for the wave-current analysis. Morison et al equation is deployed for the load computations in all cases. The above model is utilized to compute the loads on a slender cylinder for a wave with varying range of incidence current field. Computations of the moments are also done for the case when current is existed over the whole water depth of the domain.

Loading on a Fixed Vertical Slender Cylinder in an Oblique Wave-Current Field

2004 ◽  
Author(s):  
M. H. Zaman ◽  
R. E. Baddour
Keyword(s):  
Present Model ◽  
Superposition Principle ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
American Petroleum Institute ◽  
Current Field ◽  
3D Flow ◽  
Oblique Wave ◽  
Uniform Current ◽  
Offshore Industry

A study of the loading of an oblique wave-current field on a slender cylinder in a 3D flow frame is reported in this paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free waves are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. A comparison of the obtained results due to the present model to those obtained using three other models being used in the offshore industry is shown for a range of the normalized current parameters. One of these three models is proposed by the American Petroleum Institute (API), which is based on a superposition principle. Morison et al equation is deployed for the load computations in all cases. Comparisons among the obtained results in a normalized manner are shown and discussed.

Three-dimensional multi-patch isogeometric analysis of composite laminates with a discontinuous Galerkin approach

2020 ◽  
pp. 147509022092573
Author(s):  
M Amin Obohat ◽  
Ehsan Tahvilian ◽  
M Erden Yildizdag ◽  
Ahmet Ergin
Keyword(s):  
Discontinuous Galerkin ◽  
Composite Laminates ◽  
Isogeometric Analysis ◽  
Numerical Models ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Point Of View ◽  
B Spline ◽  
Elasticity Solutions ◽  
Three Dimensional Elasticity

In this study, a three-dimensional discontinuous Galerkin isogeometric analysis framework is presented for the analysis of composite laminates. Non-uniform rational B-splines are employed as basis functions for both geometric and computational implementations. From a practical point of view, modeling with multiple non-uniform rational B-spline patches is required in many different applications due to the complexity of computational domains. Then, a special numerical technique is necessary to couple different non-uniform rational B-spline patches to carry out the isogeometric analysis. In this study, therefore, one of the discontinuous Galerkin methods, namely, symmetric interior penalty Galerkin formulation is utilized to deal with multi-patch isogeometric analysis applications. In order to show the applicability of the proposed framework, composite laminates under sinusoidally distributed load with different stacking sequences are studied in the numerical examples. The predicted results are compared with those obtained by the three-dimensional elasticity solutions and various numerical models available in the literature.

scholarly journals Hydroelastic wave diffraction by a vertical cylinder

2011 ◽  
Vol 369 (1947) ◽  
pp. 2832-2851 ◽  
Author(s):  
Paul Brocklehurst ◽  
Alexander Korobkin ◽  
Emilian I. Părău
Keyword(s):  
Incident Wave ◽  
Wave Diffraction ◽  
Plate Theory ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Vertical Cylinder ◽  
Finite Depth ◽  
Cylinder Surface ◽  
Linear Elastic ◽  
Potential Flow Model

A linear three-dimensional problem of hydroelastic wave diffraction by a bottom-mounted circular cylinder is analysed. The fluid is of finite depth and is covered by an ice sheet, which is clamped to the cylinder surface. The ice stretches from the cylinder to infinity in all lateral directions. The hydroelastic behaviour of the ice sheet is described by linear elastic plate theory, and the fluid flow by a potential flow model. The two-dimensional incident wave is regular and has small amplitude. An analytical solution of the coupled problem of hydroelasticity is found by using a Weber transform. We determine the ice deflection and the vertical and horizontal forces acting on the cylinder and analyse the strain in the ice sheet caused by the incident wave.

SIMULATION AND EARLY WARNING OF NATURAL AND TECHNOGENIC INFLUENCES IN COASTAL AREAS IN THE SEA OF AZOV

2017 ◽  
Author(s):  
Tatiana Shulga ◽  
Tatiana Shulga ◽  
Leonid Cherkesov ◽  
Leonid Cherkesov
Keyword(s):  
Model Comparison ◽  
Three Dimensional ◽  
Storm Surges ◽  
Ecological Condition ◽  
Sea Of Azov ◽  
The Sea Of Azov ◽  
Waves And Currents ◽  
Coordinate Model ◽  
Passive Admixture ◽  
Comparison Of The Results

In this work, the waves and currents generated by prognostic wind in the Sea of Azov are investigated using a three-dimensional nonlinear sigma-coordinate model. The mathematical model was also used for studying the transformation of passive admixture in the Sea of Azov, caused by the spatiotemporal variations in the fields of wind and atmospheric pressure, obtained from the prediction SKIRON model. Comparison of the results of numerical calculations and the data of field observations, obtained during the action of the wind on a number of hydrological stations was carried out. The evolutions of storm surges, velocities of currents and the characteristics of the pollution region at different levels of intensity of prognostic wind and stationary currents were found. The results of a comprehensive study allow reliably estimate modern ecological condition of offshore zones, develop predictive models of catastrophic water events and make science-based solutions to minimize the possible damage.

scholarly journals Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

2021 ◽  
Vol 11 (12) ◽  
pp. 5638
Author(s):  
Selahattin Kocaman ◽  
Stefania Evangelista ◽  
Hasan Guzel ◽  
Kaan Dal ◽  
Ada Yilmaz ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Dam Break ◽  
Dam Failure ◽  
Navier Stokes ◽  
Negative Wave ◽  
Through Flow ◽  
Instantaneous Removal ◽  
Surface Patterns

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

Ice-Phase Precipitation

2017 ◽  
Vol 58 ◽  
pp. 6.1-6.36 ◽  
Author(s):  
I. Gultepe ◽  
A. J. Heymsfield ◽  
P. R. Field ◽  
D. Axisa
Keyword(s):  
Collection Efficiency ◽  
Numerical Models ◽  
Mass Density ◽  
Three Dimensional ◽  
Phase Precipitation ◽  
Microphysical Parameters ◽  
Mass Size ◽  
Ice Water ◽  
Ice Phase

AbstractIce-phase precipitation occurs at Earth’s surface and may include various types of pristine crystals, rimed crystals, freezing droplets, secondary crystals, aggregates, graupel, hail, or combinations of any of these. Formation of ice-phase precipitation is directly related to environmental and cloud meteorological parameters that include available moisture, temperature, and three-dimensional wind speed and turbulence, as well as processes related to nucleation, cooling rate, and microphysics. Cloud microphysical parameters in the numerical models are resolved based on various processes such as nucleation, mixing, collision and coalescence, accretion, riming, secondary ice particle generation, turbulence, and cooling processes. These processes are usually parameterized based on assumed particle size distributions and ice crystal microphysical parameters such as mass, size, and number and mass density. Microphysical algorithms in the numerical models are developed based on their need for applications. Observations of ice-phase precipitation are performed using in situ and remote sensing platforms, including radars and satellite-based systems. Because of the low density of snow particles with small ice water content, their measurements and predictions at the surface can include large uncertainties. Wind and turbulence affecting collection efficiency of the sensors, calibration issues, and sensitivity of ground-based in situ observations of snow are important challenges to assessing the snow precipitation. This chapter’s goals are to provide an overview for accurately measuring and predicting ice-phase precipitation. The processes within and below cloud that affect falling snow, as well as the known sources of error that affect understanding and prediction of these processes, are discussed.

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