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1
Content available On Vertical Variations of Wave-Induced Radiation Stress Tensor
100%
Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
|
2008
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tom Vol. 55, nr 3-4
83-93
EN
The flux of momentum generated by an incident wave field, commonly known as the radiation stress, plays an important role in near-shore water circulation. Many researchers use the concept of radiation stress in the calculation of cross-shore and long-shore circulation. In this paper, the traditional concept is extended to the case of vertical variation of radiation stress, and analitycal expressions for the vertical profile of radiation stress are derived. The distributions of the wave-induced radiation stress tensor with depth are studied by linear wave theory. The application of radiation stress with vertical variation is expected to play an important role in further studies of the near-shore system. Information regarding the vertical distribution of the radiation stress components ( and ) resulting from obliquely incident, shoaling waves is provided. The results show that the vertical variations of the wave-induced radiation stress tensor are significant as regards of wave propagation.
2
Content available Modelling of gravity waves in water of finite depth
100%
Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
|
2004
|
tom Vol. 51, nr 3
205-224
EN
An extension of shallow water theory proposed by Wilde (Wilde, Chybicki 2000), for finite water depth and based on the Lagrangian type formalism is presented. As in Bussinesq-type models the vertical dimension is being eliminated and the horizontal displacement is expanded in the even power series of vertical variable Y, but only two terms - with power null and two are taken into account. Based on continuity equation, vertical displacement is expressed in terms of horizontal displacement and its derivatives. The equations of motion are derived from a Hamilton principle applied to Lagrangian function being a difference of kinetic and potential energy. In order to solve the set of governing equations a direct method of variational calculus has been applied. The solutions preserve total energy. The numerical simulations have been verified experimentally, in terms of wave measurements in the flume, for various wave heights and ratios of wavelength to water depth, showing good conformity between measured and calculated values. The theory presented here can also be applied for the case of varying depth.
3
Content available remote Dwuwymiarowe nieliniowe fale długie w strefie zmiennej głębokości wody
100%
Chybicki W.
Inżynieria Morska i Geotechnika
|
2007
|
tom nr 4
215-219
PL
Dwuwymiarowy model propagacji nieliniowych, dyspersyjnych fal długich nad dnem o zmiennym profilu w opisie materialnym. Metoda korektor - predyktor Adamsa-Bashfortha-Moultona. Porównanie obliczeń numerycznych z doświadczeniami w kanale falowym. Przykłady obliczeń falowania dwuwymiarowego.
EN
2D model of propagation of non-linear dispersional long waves over the uneven bottom profile in material description. Corrector - predictor Adamas-Bashforth-Moulton's method. Numerical calculations versus test results from the wave flume. Examples of numerical calculations for 2D cases.
4
Content available remote Wysokość nadbiegania fali długiej o znacznej amplitudzie na sztywną przeszkodę pionową
100%
Chybicki W.
Inżynieria Morska i Geotechnika
|
2006
|
tom nr 5
287-290
PL
Zagadnienie wysokości nadbiegania silnie nieliniowej fali długiej na sztywną ścianę pionową. Wysokość obliczona numerycznie na podstawie równania Boussinesqa w opisie Langrange'a, po uwzględnieniu wyrażeń nieliniowych wyższych rzędów.
EN
The problem of run-up of highly non-linear long wave on the rigid vertical wall. The height calculated numerically based on Bussinesque-type equation derived in Langrangian description, including higher orders non-linear expression.
5
Content available Certain solutions of periodic long waves with non-linear dispersion
100%
Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
|
2004
|
tom Vol. 51, nr 4
307-315
EN
The paper describes some special solutions of the long water waves theory proposed by Wilde. The wave equation is derived with the help of a variational formulation of the problem with the Langrangian being the difference between the kinetic and potential energies. In order to look for travelling wave solutions the simple transformation is made. The solutions have been found in the same way as in the KdV equation. Solutions for different wave amplitudes are presented in the paper. The special cases of solutions are solitary waves. It is proved that bounded solutions of an equation can represent periodic or solitary waves and both length and velocity of waves increase when the height of waves increases.
6
Content available Simple water waves in Lagrangian description
100%
Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
|
2006
|
tom Vol. 53, nr 4
381-387
EN
Details of the model of long water waves in the Lagrangian description are presented. The equation of motion is derived from variational formulation of the problem. Only two important cases are considered: when the water depth changes uniformly in space or the depth is constant. For quasilinear hyperbolic system obtained in this description the Riemann invariants and equation of simple waves are found. For constant depth, the Riemann invariants are exactly the same as in the Euler description, however, the velocity of wave propagation is different. In case of uniform slope the velocity, as well as the Riemann invariants are different. In the Lagrangian description the free surface is described in parametric form.
7
Content available remote Fale długie nad dnem o zmiennym profilu
100%
Chybicki W.
Inżynieria Morska i Geotechnika
|
2004
|
tom nr 6
285-288
PL
Nowy model fal długich nad zmiennym dnem w opisie Langrange'a. Równania ruchu w zapisie wariacyjnym z funkcją Langrange' a. Porównanie wyników obliczeń numerycznych z doświadczeniami w kanale falowym.
EN
New model for long waves over the uneven bottom described in Lagrangian description. Equations of motion in variational notation with Lagrange's function. Comparison of the results of numerical calculations with experiments made in wave flume.
8
Content available Run-Up of Linear Long Waves on Uniform Slope in Lagrangian Description
100%
Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
|
2006
|
tom Vol. 53, nr 2
97-104
EN
The case of linear, two-dimensional long waves on a uniform slope is considered. It is assumed that the fluid is nonviscous and incompressible. In the present paper the description of the long wave proposed by Wilde (Wilde, Chybicki 2004) is based on the fundamental assumption that the vertical material lines of fluid remain vertical during the entire motion. The equations of motion are derived with the help of a variational formulation of the problem. The Lagrangian is the difference between the kinetic and potential energy of the fluid. In the paper a correction followed from dispersion to the results obtained by Shuto is presented.
9
Content available Long water waves as a structure fluid interaction problem
63%
Wilde P. , Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
|
2004
|
tom Vol. 51, nr 2
95-118
EN
The paper describes a new formulation of the theory of long shallow water waves, which is based on the fundamental assumption that vertical material lines of fluid remain vertical during the entire motion. To make the problem consistent from the point of view of physics the case of waves in a flume due to the motion of a piston type generator is considered. At the piston the material line of water particles remains vertical during the entire motion and thus the generation follows the assumption in the description of the motion of water in the flume. Wave equations are derived with the help of a variational formulation of the problem in a material description. The Lagrangian is the difference between the kinetic and potential energies of the fluid and the mechanical system that describes a very simplified wave generator. The basic assumption simplifies the geometry of the displacement field. The definitions of generalized forces follow from variational calculus. The procedure ensures that the energy is preserved. A simple discrete formulation of the problem is based on the finite element method and the corresponding approximate expressions for energies.
10
Content available Horizontal motion of a rigid block resting on accelerating subsoil
63%
Sawicki A. , Chybicki W.
Archives of Hydro-Engineering and Environmental Mechanics
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2005
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tom Vol. 52, nr 2
147-160
EN
The horizontal motion of the system: rigid block-accelerating subsoil is analysed, using the most simple approach. First, the method of analysis is described and illustrated for constant coefficient of friction between the block and subsoil. Then, the changing coefficient of friction is taken into account, and its influence on the motion shown. In the next step of analysis, the influence of horizontal force on permanent relative displacement of the block with respect to subsoil is illustrated for constant and changing coefficients of friction. The method presented in this paper form a basis for critical discussion of the Newmark approach, that is a kind of standard in earthquake geotechnics.
11
Content available remote Studium modelowania deformacji piasku przed osiągnięciem stanu granicznego
63%
Sawicki A. , Chybicki W.
Inżynieria Morska i Geotechnika
|
2003
|
tom nr 3-4
190-194
PL
Zaproponowano empiryczną metodę modelowania całkowitych odkształceń piasku przy obciążeniu, przed osiągnięciem stanu granicznego. Punktem wyjścia są ogólne zależności pomiędzy przyrostami naprężeń i odkształceń. Funkcje występujące w tych równaniach wyznacza się z danych doświadczalnych, odpowiadających szczególnym ścieżkom naprężenia w aparacie trójosiowym. Pokazano przykład wyznaczenia takich funkcji dla luźnego piasku "Skarpa". Model poddano częściowej weryfikacji, porównując jego predykcje dla innej ścieżki naprężenia z wynikami doświadczeń. Otrzymano dobrą zgodność w zakresie przewidywania odkształceń postaciowych, natomiast gorszą dla odkształceń objętościowych.
EN
Empirical method of modelling pre-failure deformations of sand is proposed. The starting point are general relations between the stress and strain increments. Functions appearing in these incremental relations are determined experimentally from specific stress paths in the triaxial apparatus. As illustration, these functions were determined for loose "Skarpa" sand. The model was partly verified, by comparing its prediction with experimental results obtained for stress paths different from those used during model calibration. A good agreement was obtained for deviatoric strains. In the case of volumetric strains, agreement was worse, and therefore further refinement of the model necessary.
12
Content available Laboratory investigations of deep-water wave transformation and stability
51%
Wilde P. , Sobierajski E. , Chybicki W. , Sobczak Ł.
Archives of Hydro-Engineering and Environmental Mechanics
|
2003
|
tom Vol. 50, nr 3
287-313
EN
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.
13
Content available remote Wybrane zastosowania w nauce i dydaktyce kanału rumowiskowo-przepływowego
51%
Wróblewski A. , Chybicki W. , Srokosz P.
Inżynieria Morska i Geotechnika
|
2015
|
tom nr 4
592--596
PL
Wybrane zastosowania laboratoryjnego kanału rumowiskowo-przepływowego, stanowiącego podstawowe wyposażenie laboratorium hydrologicznego Uniwersytetu Warmińsko-Mazurskiego w Olsztynie. Szerokie możliwości prowadzenia badań eksperymentalnych związanych z modelowaniem wielu zjawisk hydrodynamicznych, w tym wpływu propagacji fal na zjawisko pionowego mieszania wody. Pomiar pola prędkości ruchu wody przy pomocy laserowych instrumentów PIV. Wykorzystanie laboratoryjnego kanału rumowiskowo-przepływowego w dydaktyce.
EN
Selected applications of the laboratory flume channel, which is the basic equipment of the hydrological laboratory of the University of Warmia and Mazury in Olsztyn. The extensive experimental research opportunities related to the hydrodynamic modelling of many phenomena, including the impact of wave propagation on the phenomenon of vertical water mixing. The registration of the velocity field of water movement using PIV laser instruments. The use of the laboratory flume channel in teaching many subjects realized in the fields of Civil Engineering, Environmental Engineering and Environmental Protection.
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