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Wyszukujesz frazę "water wave" wg kryterium: Temat


Tytuł:
Laboratory investigations of deep-water wave transformation and stability
Autorzy:
Wilde, P.
Sobierajski, E.
Chybicki, W.
Sobczak, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/240986.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
laboratory investigations
deep-water wave transformation
deep-water wave stability
Opis:
The authors performed laboratory investigations and the analysis of the transformation of deep-water waves in the flume of the Institute of Hydro-Engineering. Special wave trains were generated by our piston-type wavemaker. Due to the transformation the wave profiles changed along the path of propagation. At first, the changes appeared at the ends of the wave train. Far from the generator they intruded into the middle interval of initially regular waves. Finally, the whole wave train consisted of a set of irregular groups. To study the instability problem the wave trains were modulated by superposition of wave groups with very small amplitudes. The number of waves in a group was a very important parameter. When the number was proper, even small amplitudes of modulation resulted in strong development of amplitudes of wave groups. In our theoretical analysis the non-linear Schroedinger equation was used. The comparison of laboratory and theoretical results proved that this equation is useful but it does not describe the phenomenon in the best way. There have been many attempts to construct a numerical procedure that describes the propagation of water waves. Very often the numerical algorithm is not stable and the results of calculation diverge from the expected behaviour. The authors believe that in many cases the instability is due to the physical loss of stability of the wave train and thus it is necessary to have a good understanding of the physics of the studied motion.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 3; 287-313
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave-induced stresses and liquefaction in seabed according to the biot-type approach
Autorzy:
Sawicki, A.
Mierczyński, J.
Powiązania:
https://bibliotekanauki.pl/articles/241059.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
seabed mechanics
water wave
liquefaction
Opis:
The problem of wave-induced stresses and liquefaction in the seabed according to the Biot-type approach is discussed. The first part of the paper deals with critical analysis of approaches presented in recent literature. It is shown that such approaches do not lead to proper description of the process of wave-induced pore-pressure generation and subsequent liquefaction of seabeds. The second part of this paper deals with the generalisation of the Biot-type approach to the case of shear modulus depending on mean effective stress.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 2; 131-145
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Interactions between Gravity Waves in Water of Constant Depth
Autorzy:
Szmidt, K.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/241222.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
nonlinear water wave
wave interaction
material variables
potential solution
Opis:
The paper deals with interactions between water waves propagating in fluid of constant depth. In formulation of this problem, a nonlinear character of these interactions is taken into account. In particular, in order to simplify a solution to nonlinear boundary conditions at the free surface, a system of material coordinates is employed as independent variables in the description of the phenomenon. The main attention is focused on the transient solutions corresponding to fluid motion starting from rest. With respect to the initial value problem considered, we confine our attention to a finite fluid domain. For a finite elapse of time, measured from the starting point, the solution in a finite fluid area mimics a solution within an infinite domain, inherent for wave propagation problems. Because of the complicated structure of equations describing nonlinear waves, an approximate formulation is considered, which is based on a power series expansion of dependent variables with respect to a small parameter. Such a solution is assumed to be accurate in describing the main features of the phenomenon. Numerical experiments are conducted to illustrate the approximate formulation developed in this paper.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2015, 62, 1-2; 3-25
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the generation of water waves in a flume
Autorzy:
Wilde, P.
Wilde, M.
Powiązania:
https://bibliotekanauki.pl/articles/241118.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water wave
flume
wavemaker
horizontal motion
piston
Opis:
The present paper proposes a simple model for the calculation of a time series to control the horizontal motion of the piston of a wavemaker. It is assumed that the initial conditions correspond to water at rest. It is assumed that parameters of kinematics of the fluid (displacement, velocity and acceleration fields) at the initial time are equal to zero. In the first interval the amplitudes grow to an asymptote that corresponds to a regular monochromatic wave. In the second interval the waves decay. Calculated time series were fed in to the control system of our wavemaker and the measured horizontal displacements of the piston compared. The control series was supplemented by terms corresponding to the Stokes type solution by addition of terms with multiples of the basic frequency.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2001, 48, 4; 69-83
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the SPH Approximations in ModelingWaterWaves
Autorzy:
Szmidt, K.
Powiązania:
https://bibliotekanauki.pl/articles/241299.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water wave
SPH modeling
consistency
kernel correction
Opis:
This paper presents an examination of approximation aspects of the Smoothed Particle Hydrodynamics (SPH) in modeling the water wave phenomenon. Close attention is paid on consistency of the SPH formulation and its relation with a correction technique applied to improve the method accuracy. The considerations are confined to flow fields within finite domains with a free surface and fixed solid boundaries with free slip boundary conditions. In spite of a wide application of the SPH method in fluid mechanics, the appropriate modeling of the boundaries is still not clear. For solid straight line boundaries, a natural way is to use additional (virtual, ghost) particles outside the boundary and take into account mirror reflection of associated field variables. Such a method leads to good results, except for a vicinity of solid horizontal bottoms where, because of the SPH approximations in the description of pressure, a stratification of the fluid material particles may occur. In order to illustrate the last phenomenon, some numerical tests have been made. These numerical experiments show that the solid fluid bottom attracts the material particles and thus, to prevent these particles from penetration into the bottom, a mutual exchange of positions of real and ghost particles has been used in a computation procedure.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2013, 60, 1-4; 63-86
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On variational formulation in water wave mechanics
Autorzy:
Wilde, P.
Szmidt, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/241323.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water wave
variational formulation
spatial and material description
Opis:
In this paper variational formulations for surface gravitational waves in inviscid incompressible fluids are investigated. The formulations are introduced with the help of the principle of virtual work. The starting point are equations of motion multiplied by a field of virtual displacements and integrated over the region occupied by the fluid. In derivations of the virtual work equation careful attention is paid to mutual relations between Eulerian and Lagrangian descriptions. The integration of the equation with respect to time leads to the expression for the Lagrangian function and then the Hamilton's principle. The case of a potential flow and spatial description provides a generalisation of the Lagrangian given by Luke (1967).
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2004, 51, 1; 55-74
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite Difference Analysis of Surface Wave Scattering by Underwater Rectangular Obstacles
Autorzy:
Szmidt, K.
Powiązania:
https://bibliotekanauki.pl/articles/241339.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water wave
scattering of waves
finite difference method
Opis:
This paper deals with the problem of the scattering of surface water waves by underwater obstacles. The main goal of the investigations is to estimate the efficiency of such structures in protecting sea shelf zones from open sea waves. A useful measure of the protection is the ratio of the square of the amplitude of the transmitted wave to the square of the amplitude of the arriving wave. The problem is formulated in terms of the finite difference method. It is shown that the discrete approach to the problem leads to eigenvalue problems for two matrices resulting from the discrete description. As compared to analytical formulation, the discrete method may be convenient in application to unsteady problems and obstacles of complicated geometry.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2010, 57, 3-4; 179-198
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical analysis on experiments in transformation of deep-water-waves
Autorzy:
Wilde, P.
Powiązania:
https://bibliotekanauki.pl/articles/241349.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water wave
stability
transformation
wave groups
non-linear Schrödinger differential equation
Opis:
The aim of the paper is to discuss the usefulness of the non-linear Schrödinger differential equation in the study of transformations of progressive deep water waves. Its solution compared with a regular Stokes type wave is essentially restricted to the first order approximation of the second one. The difference is that the Schrödinger equation introduces the concepts of a carrier wave and complex amplitude. In this way the dispersion relation of the third order Stokes expansion is taken into account. The analysis starts with regular, non breaking Stokes waves with large amplitudes as measured in our laboratory. The third order approximation is considered and compared with the corresponding solution of the Schrödinger equation. Then small periodic modifications are introduced in the time series fed into the control system of the generator. The approximation by trigonometric series is applied and the simplified analysis of superposition of very small modifications is used (higher powers of modifications are neglected). The Schrödinger non-linear equation is used in this analysis. The comparison of experimental and calculated envelopes is good, but for the surface elevations in space it is not as good. The approximation by trigonometric series is also applied to study the case of larger modifications. Finally the solutions of the Schrödinger equation corresponding to perfect solitons, are compared with the experimental data for cases where the measured surface elevations look almost like periodic solitons. This gives a reasonable approximation of the real behaviour in a very short space interval. It is not easy to get a good numerical description for the wave problem discussed as the waves are physically unstable. The results of the presented research will be used to establish an effective numerical procedure, stress the approximations introduced by the application of the Schrödinger differential equation and show how the theoretical solutions should be compared with the measured data.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2005, 52, 3; 213-242
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of an Element-free Galerkin Method to Water Wave Propagation Problems
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241246.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
gravity water wave
transient problem
element-free Galerkin method
Opis:
The paper is concerned with the problem of gravitational wave propagation in water of variable depth. The problem is solved numerically by applying an element-free Galerkin method. First, the proposed model is validated by comparing its predictions with experimental data for the plane flow in water of uniform depth. Then, as illustrations, results of numerical simulations performed for plane gravity waves propagating through a region with a sloping bed are presented. These results show the evolution of the free-surface elevation, displaying progressive steepening of the wave over the sloping bed, followed by its attenuation in a region of uniform depth. In addition, some of the results of the present model are compared with those obtained earlier by using the conventional finite element method.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2013, 60, 1-4; 87-105
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transformation of long waves in a canal of variable section
Autorzy:
Szmidt, K.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/241144.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
long water wave
canal of variable section
enforcement of wave height
material variables
Opis:
The paper deals with long water waves propagating in a straight canal of constant depth and variable section. In the formulation of this problem, a simplified, one-dimensional model is considered that is based on the assumption of a “columnar” fluid motion. To this end, a system of material coordinates is employed as independent variables in the description of this phe- nomenon. The main attention is focused on transient solutions corresponding to a fluid motion starting from rest. With respect to the initial value problem considered, we confine our attention to a finite domain fluid motion induced by a piston-type generator placed at the beginning of the canal. For a finite elapse of time, measured from the starting point, the solution in the finite fluid area mimics a solution within an infinite domain, inherent for wave propagation problems. The main goal of our investigations is to describe the evolution of the free surface (the wave height) at the smallest section of the canal. Numerical examples are provided to illustrate the model formulation developed in this paper. The accuracy of this approximate description is assessed by comparing its results with data obtained in hydraulic experiments performed in a laboratory flume.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2016, 63, 1; 3-18
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Lagrangian Finite Element Analysis of Gravity Waves in Water of Variable Depth
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241185.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
gravity water wave
variable water depth
transient problem
Lagrangian formulation
finite element method
Opis:
The paper is concerned with the problem of gravitational wave propagation in water of variable depth. The problem is formulated in the Lagrangian description, and the ensuing equations are solved numerically by a finite element method. In computations a convecting mesh that follows the material fluid particles is used. As illustrations, results of numerical simulations carried out for plane gravity waves propagating over bottoms of simple geometry are presented. For parameters typical of a laboratory flume, the transformation of a transient wave, generated by a single movement of a piston-like wave maker, is investigated. The results show the evolution of the free-surface elevation, displaying steepening of the wave over sloping beds and its gradual attenuation in regions of uniform depth.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2009, 56, 1-2; 43-61
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of Water Flows around a Circular Cylinder with the SPH Method
Autorzy:
Szmidt, T.
Hedzielski, B.
Powiązania:
https://bibliotekanauki.pl/articles/241295.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
transient water wave
SPH modeling
boundary conditions
approximation of shear forces
Opis:
The paper describes the SPH modeling of a plane problem of fluid flow around a rigid circular cylinder. In the model considered, the cylinder is placed in a rectangular fluid domain at a certain distance from a horizontal plane boundary, and it is subjected to fluid flow forces. The fluid motion is induced by a piston type generator. The generator - fluid system starts to move from rest at a certain moment of time. The work aims at a discrete description of the fluid flow around the cylinder and, at the same time, calculation of the pressure distribution along the circumference of the cylinder and the resultant of the pressure on the cylinder. In order to solve the initial value problem considered, a new SPH formulation of boundary conditions on the cylinder surface is proposed which match the physical condition for the fluid velocity at this boundary. For a viscous fluid, an approximate description of the stress tensor is formulated which allows to reduce the differentiation of field functions to the first order in calculating the shear forces in the SPH approach.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2014, 61, 1-2; 39-60
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Initial boundary value problems for vortex motion of an ideal fluid in bounded domains
Autorzy:
Szmidt, K.
Powiązania:
https://bibliotekanauki.pl/articles/241010.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
vortex motion
incompressible perfect fluid
bounded domains
boundary value problems
water wave
Opis:
The paper deals with the problem of vortex motion of an incompressible perfect fluid in bounded domains. The research is confined to chosen cases of steady velocity fields within rectangular, circular and elliptic regions with rigid boundaries. The solution to the initial-value problem of the fluid flow for the assumed velocity fields is the primary object of this paper. It is demonstrated that individual particles of the fluid have their own periods of motion and thus, one should be careful in describing such problems by means of discrete methods, especially in the Lagrangian variables. The problem discussed has its origin in numerical analysis of water waves by means of the finite difference or the finite element method.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2001, 48, 1; 19-33
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Incompressible SPH Model for Simulating Violent Free-Surface Fluid Flows
Autorzy:
Staroszczyk, R.
Powiązania:
https://bibliotekanauki.pl/articles/241132.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
gravity water wave
free surface
incompressible flow
Lagrangian description
smoothed particle hydrodynamics
Opis:
In this paper the problem of transient gravitational wave propagation in a viscous incompressible fluid is considered, with a focus on flows with fast-moving free surfaces. The governing equations of the problem are solved by the smoothed particle hydrodynamics method (SPH). In order to impose the incompressibility constraint on the fluid motion, the so-called projection method is applied in which the discrete SPH equations are integrated in time by using a fractional-step technique. Numerical performance of the proposed model has been assessed by comparing its results with experimental data and with results obtained by a standard (weakly compressible) version of the SPH approach. For this purpose, a plane dam-break flow problem is simulated, in order to investigate the formation and propagation of a wave generated by a sudden collapse of a water column initially contained in a rectangular tank, as well as the impact of such a wave on a rigid vertical wall. The results of simulations show the evolution of the free surface of water, the variation of velocity and pressure fields in the fluid, and the time history of pressures exerted by an impacting wave on a wall.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2014, 61, 1-2; 61-83
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear ship wake waves as a model of rogue waves and a source of danger to the coastal environment: a review
Autorzy:
Soomere, T.
Powiązania:
https://bibliotekanauki.pl/articles/48354.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Sopot
nonlinear ship
wave
extreme wave
shallow water wave
conference
Baltic Sea
marine ecosystem
coastal environment
ship traffic
speed ship
coastal area
Opis:
A substantial part of the energy of wake waves from high-speed ships sailing in shallow water is concentrated in nonlinear components which at times have a solitonic nature. Recent results of investigations into solitonic wave interactions within the framework of the Kadomtsev-Petviashvili equation and their implications for rogue wave theory are reviewed. A surface elevation four times as high as the counterparts occurs if the properties of the interacting waves are specifically balanced. The slope of the water surface may increase eightfold. The resulting structure may persist for a long time. Nonlinear wake components may exert a considerable influence on the marine ecosystem in coastal areas.
Źródło:
Oceanologia; 2006, 48, S
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł

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